Migrate to OSS Community Develocity Instance

[jprinet]

Migrate to the OSS Community Develocity Instance

This PR migrates Develocity Build Scan® and Build Cache support
for this project to the OSS Community Develocity Instance at
https://community.develocity.cloud under project ID testcontainers.

What this PR changes

• Updates settings.gradle to point at https://community.develocity.cloud with project ID testcontainers and adds IP address obfuscation
• Upgrades develocity-gradle-plugin to 4.4.1 and common-custom-user-data-gradle-plugin to 2.6.0 in settings.gradle
• Renames GRADLE_ENTERPRISE_ACCESS_KEY → DEVELOCITY_ACCESS_KEY in all GitHub Actions workflow files
• Updates the "Revved up by Develocity" badge in the README to link to the filtered Build Scan list for this project on the community instance

Step 1 — Get an access key for community.develocity.cloud

Build Scan publishing and Build Cache writes from CI need a Develocity access key.

1. Visit https://community.develocity.cloud.
2. Sign in as the CI service account that the Develocity Solutions team has provisioned for your project — that account's project memberships and permissions are already set up for this migration. The access key inherits those memberships and permissions.
3. From the user menu in the top-right, open My settings → Access keys.
4. Click Generate access key, give it a description (e.g. GitHub Actions), and copy the generated key. Keep this tab open until you complete Step 2 — the key is only shown once.

Step 2 — Set the GitHub Actions secret on this repository

CI uses a repository secret named DEVELOCITY_ACCESS_KEY to authenticate to community.develocity.cloud.

1. Open this repository on GitHub and click Settings.
2. In the left sidebar, click Secrets and variables → Actions.
3. Click New repository secret (or update the existing GRADLE_ENTERPRISE_ACCESS_KEY if present — but note the name must change to DEVELOCITY_ACCESS_KEY).
4. Set Name to: DEVELOCITY_ACCESS_KEY
5. Set Secret to the value community.develocity.cloud=PASTE_THE_ACCESS_KEY_FROM_STEP_1_HERE (the community.develocity.cloud= prefix is required — this is the most common point of failure).
6. Click Add secret (or Update secret).

Step 3 — Provision an access key for local builds

Developers building locally should run: ./gradlew provisionDevelocityAccessKey

Note on the CI run on this PR

This PR was prepared from a fork. Forks can't read repository secrets, so the workflow run on this PR cannot publish to community.develocity.cloud even after setting the secret. To get CI verification before merging, push the branch build/migrate-to-oss-community-develocity-instance to a temporary branch on the main repo and re-run.

[jprinet]

tagging you @kiview for visibility 👋