Prebuilt Spine test data should automatically be generated during build (DEF-3078)

[britzl]

Currently there are some Spine tests in in gamesys that needs prebuilt data (rigscene, meshset etc) to work. These prebuilt files can be generated using a script located under the test folder for gamesys, which will run bob-light on a simple project and copy the resulting files to the correct folder.

If the protobuf messages for rig is updated, these prebuilt files needs to be regenerated once again, and committed the the repo. This is not ideal, it would be much better if this script/step is automatically run when building+running the gamesys tests.

[JCash]

We have no test data left in the engine.
All future tests should be in the extension.