docs: add Helm chart installation

Signed-off-by: Krypton <root@krypton.ninja>

Author: kkrypt0nn

web/docs/installation.mdx

@@ -56,6 +56,8 @@ Both checks are required before proceeding with the installation.
 
 import { InstallationSnippet } from '@site/src/components/Installation';
 
+### Directly using the manifest
+
 Install the plugin using `kubectl` by applying the manifest for the latest
 release:
 
@@ -98,6 +100,18 @@ deployment "barman-cloud" successfully rolled out
 
 This confirms that the plugin is deployed and ready to use.
 
+### Using the Helm Chart
+
+The plugin can be installed using the provided [Helm chart](https://github.com/cloudnative-pg/charts/tree/main/charts/plugin-barman-cloud):
+
+```sh
+helm repo add cnpg https://cloudnative-pg.github.io/charts
+helm upgrade --install barman-cloud \
+  --namespace cnpg-system \
+  --create-namespace \
+  cnpg/plugin-barman-cloud
+```
+
 ## Testing the latest development snapshot
 
 You can also test the latest development snapshot of the plugin with the

web/versioned_docs/version-0.10.0/installation.mdx

@@ -5,12 +5,13 @@ sidebar_position: 20
 # Installation
 
 :::important
+
 1. The plugin **must** be installed in the same namespace as the CloudNativePG
    operator (typically `cnpg-system`).
 
 2. Keep in mind that the operator's **listening namespaces** may differ from its
    installation namespace. Double-check this to avoid configuration issues.
-:::
+   :::
 
 ## Verifying the Requirements
 
@@ -54,7 +55,9 @@ Both checks are required before proceeding with the installation.
 
 ## Installing the Barman Cloud Plugin
 
-import { InstallationSnippet } from '@site/src/components/Installation';
+import { InstallationSnippet } from "@site/src/components/Installation";
+
+### Directly using the manifest
 
 Install the plugin using `kubectl` by applying the manifest for the latest
 release:
@@ -98,6 +101,19 @@ deployment "barman-cloud" successfully rolled out
 
 This confirms that the plugin is deployed and ready to use.
 
+### Using the Helm Chart
+
+The plugin can be installed using the provided [Helm chart](https://github.com/cloudnative-pg/charts/tree/main/charts/plugin-barman-cloud):
+
+```sh
+helm repo add cnpg https://cloudnative-pg.github.io/charts
+helm upgrade --install barman-cloud \
+  --namespace cnpg-system \
+  --create-namespace \
+  --version 0.4.0 \
+  cnpg/plugin-barman-cloud
+```
+
 ## Testing the latest development snapshot
 
 You can also test the latest development snapshot of the plugin with the

web/versioned_docs/version-0.5.0/installation.mdx

@@ -56,6 +56,8 @@ Both checks are required before proceeding with the installation.
 
 import { InstallationSnippet } from '@site/src/components/Installation';
 
+### Directly using the manifest
+
 Install the plugin using `kubectl` by applying the manifest for the latest
 release:
 
@@ -98,6 +100,19 @@ deployment "barman-cloud" successfully rolled out
 
 This confirms that the plugin is deployed and ready to use.
 
+### Using the Helm Chart
+
+The plugin can be installed using the provided [Helm chart](https://github.com/cloudnative-pg/charts/tree/main/charts/plugin-barman-cloud):
+
+```sh
+helm repo add cnpg https://cloudnative-pg.github.io/charts
+helm upgrade --install barman-cloud \
+  --namespace cnpg-system \
+  --create-namespace \
+  --version 0.1.0 \
+  cnpg/plugin-barman-cloud
+```
+
 ## Testing the latest development snapshot
 
 You can also test the latest development snapshot of the plugin with the

web/versioned_docs/version-0.7.0/installation.mdx

@@ -56,6 +56,8 @@ Both checks are required before proceeding with the installation.
 
 import { InstallationSnippet } from '@site/src/components/Installation';
 
+### Directly using the manifest
+
 Install the plugin using `kubectl` by applying the manifest for the latest
 release:
 
@@ -98,6 +100,19 @@ deployment "barman-cloud" successfully rolled out
 
 This confirms that the plugin is deployed and ready to use.
 
+### Using the Helm Chart
+
+The plugin can be installed using the provided [Helm chart](https://github.com/cloudnative-pg/charts/tree/main/charts/plugin-barman-cloud):
+
+```sh
+helm repo add cnpg https://cloudnative-pg.github.io/charts
+helm upgrade --install barman-cloud \
+  --namespace cnpg-system \
+  --create-namespace \
+  --version 0.2.0 \
+  cnpg/plugin-barman-cloud
+```
+
 ## Testing the latest development snapshot
 
 You can also test the latest development snapshot of the plugin with the

web/versioned_docs/version-0.9.0/installation.mdx

@@ -5,12 +5,13 @@ sidebar_position: 20
 # Installation
 
 :::important
+
 1. The plugin **must** be installed in the same namespace as the CloudNativePG
    operator (typically `cnpg-system`).
 
 2. Keep in mind that the operator's **listening namespaces** may differ from its
    installation namespace. Double-check this to avoid configuration issues.
-:::
+   :::
 
 ## Verifying the Requirements
 
@@ -54,7 +55,9 @@ Both checks are required before proceeding with the installation.
 
 ## Installing the Barman Cloud Plugin
 
-import { InstallationSnippet } from '@site/src/components/Installation';
+import { InstallationSnippet } from "@site/src/components/Installation";
+
+### Directly using the manifest
 
 Install the plugin using `kubectl` by applying the manifest for the latest
 release:
@@ -98,6 +101,19 @@ deployment "barman-cloud" successfully rolled out
 
 This confirms that the plugin is deployed and ready to use.
 
+### Using the Helm Chart
+
+The plugin can be installed using the provided [Helm chart](https://github.com/cloudnative-pg/charts/tree/main/charts/plugin-barman-cloud):
+
+```sh
+helm repo add cnpg https://cloudnative-pg.github.io/charts
+helm upgrade --install barman-cloud \
+  --namespace cnpg-system \
+  --create-namespace \
+  --version 0.3.1 \
+  cnpg/plugin-barman-cloud
+```
+
 ## Testing the latest development snapshot
 
 You can also test the latest development snapshot of the plugin with the