Refactor Templates to Layouts, Review and Cleanup

- Fix tgogenerator
- Fix UI for ForceGroup and Layouts
- Fix ammo depot handling
- Split bigger files in smaller meaningful files (TGO, layouts, forces)
- Renamed Template to Layout
- Renamed GroundGroup to TheaterGroup and GroundUnit to TheaterUnit
- Reorganize Layouts and UnitGroups to a ArmedForces class and ForceGroup similar to the AirWing and Squadron
- Reworded the UnitClass, GroupRole, GroupTask (adopted to PEP8) and reworked the connection from Role and Task
- added comments
- added missing unit classes
- added temp workaround for missing classes
- add repariable property to TheaterUnit
- Review and Cleanup

Added serialization for loaded templates

Loading the templates from the .miz files takes a lot of computation time and in the future there will be more templates added to the system. Therefore a local pickle serialization for the loaded templates was re-added:
- The pickle will be created the first time the TemplateLoader will be accessed
- Pickle is stored in Liberation SaveDir
- Added UI option to (re-)import templates

resources/units/groups/Freya.yaml

@@ -0,0 +1,16 @@
+name: Freya
+role: AntiAir
+tasks:
+  - SHORAD
+units:
+  - EWR FuMG-401 Freya LZ
+  - 2 cm Flakvierling 38
+  - 8.8 cm Flak 18
+  - LUV Kubelwagen 82
+  - Sd.Kfz.7 Tractor
+  - LUV Kettenrad
+  - PU Maschinensatz_33
+  - AAA SP Kdo.G.40
+  - Infantry Mauser 98
+layouts:
+  - Freya EWR Site