Encounter stuff

[Eddio0141]

This mainly brings

• A scene manager
• Trigger that you can use to trigger a transition to enemy battle scene

Additional information

• I added a sprite asset which is there just for testing
• There isn't a transition effect implemented, only the code and components for transition and stuff
• Added a testing scene with basic character movement script

[c-hurrell]

Okay will merge with dev branch testing stuff is all good