Configurable Activities

[heinezen]

Makes the activity system configurable with nyan.

• [x] Converter: Configure activities as abilities for game entities
  • [x] Load new nyan data API objects (see https://github.com/SFTtech/openage/pull/1608)
  • [x] Assign default activity to game entity definitions in modpack
  • [x] Export new engine modpack version
• [x] Activity system
  • [x] Define condition/event function per branch for XorGate/XorEventGate
  • [x] Add built-in condition functions
  • [x] Add built-in event primer functions
• [x] Entity creation
  • [x] Get data from activity objects from nyan API
  • [x] Create activity from nyan definition
  • [x] Cache created activities