Multi web app environment test

[tusmester]

Build a new multi-appdomain environment for a repository and validate that the index and messaging works correctly.

• search service mode (mandatory)
• local indexing + messaging (optional)

Acceptance

• special environment config and processes are documented
• repeatable tests powered by a script
  • parallel read/write operations on both app domains
• test locally and on a test server
• review logs and fix errors