Added decisions to stop colonial nations from further expanding (by removing their colonists and making development cost very high)

Mod is now implemented as decisions available for the colonial overlord instead of events that happen to the colonial subject.

Corrected mod name

Changed thumbnail from .jpg to .png

Added thumbnail and its line in descriptor file

First version of ColonialBordersFixRedux

Changes with respect to Hebizuki's ColonialBordersFix
- corrected checks for determining colonial region
- changed scope to only check for provinces belonging to colonial nation
- included colonial Australia for completeness
- capital change now only checks for valid provinces in same colonial region, preventing a bug
- updated capital city definitions to latest province numbers
- changed capital of colonial Colombia from Cartagena to Bogota for historical reasons
- included missing capital city definitions (Colonial Cascadia and Colonial Australia)
- removed third event (change USA culture to American)