Create a plugin integration test project

[butler54]

Issue description / feature objectives

The plugin architecture allows independent 3rd parties to introduce plugins. However, there is no centralised test harness. Create a project that is ONLY testing where all plugins can be installed to test for:

1. Dependency conflicts (known and unknown)
2. Validate basic expected behaviour.

Note this is NOT meant to replace unit tests within the plugins, however, can be used for integration testing.

Will require CI hooks that trigger off of updates to release branches for all of the appropriate plugins.