feat: update testbench navigation links and add installation and workflow guides

Author: fmallmann

home/modules/explanation/partials/nav.adoc

@@ -1,5 +1,5 @@
 *** xref:architecture:index.adoc[]
 include::architecture:partial$nav.adoc[]
 
-*** xref:testbench:index.adoc[Testbench Architecture]
-include::testbench:partial$nav.adoc[]
+*** xref:testbench:architecture:index.adoc[Testbench Architecture]
+include::testbench:architecture:partial$nav.adoc[]

home/modules/how-to-guides/partials/nav.adoc

@@ -8,3 +8,6 @@
 ** xref:agent-runtime-operator:agent-gateways:how-to-guide.adoc[]
 ** xref:agent-runtime-operator:tool-servers:how-to-guide.adoc[]
 ** xref:agent-runtime-operator:tool-gateways:how-to-guide.adoc[]
+
+** xref:testbench:how-to:install.adoc[Install the Testbench]
+** xref:testbench:how-to:first-workflow.adoc[Create Your First TestWorkflow]