bugfix: Fix obs overlay font adjustment after merge, normalize notification content, fix spectre multi notifs, add per type toggles and observer notification keybinds

[MrS-ibra]

This PR:

• Fixes observer overlay font adjustment after merge.

• Fixes a bug where the spectre notification would appear 3 times.

• Changes notification content casing and normalizes it.

• Adds a new notification for a GLA faction aquiring power "Player now has power".

• Adds a notification for the player getting worker/dozer hunted.

• Adds an early game milestone notifications skip in case of modded maps that start with high ranks or income.

• Adds options to allow observers to disable specific notification types independently.
  Defaults to yes and can be disabled by changing value to no
  ObserverNotificationSpecialPowerUsage = no
  ObserverNotificationSpecialPowerPurchase = no
  ObserverNotificationMilestone = no

• Adds brightness for obs and notification overlay for better visibility.

• Removes the following notifications:
  Reached 20k cpm
  Reached 50k cpm
  Reached 100k cpm
  Is floating 100k
  Used, activated , deployed :
  Frenzy
  Spy drone
  Spy satellite
  GPS scrambler
  Emergency repair
  Inf drop
  Tank drop
  USA inf drop

• Adds Shift+Left/Right keybinds to adjust observer notification font size in game

• Persists observer stats and notification font sizes to preferences to survive game restarts

The key mapping can be changed in CommandMap.ini
Example of changing the key mapping to Shift =/-

CommandMap INCREASE_OBSERVER_NOTIFICATION_FONT
Key = KEY_EQUAL
Transition = DOWN
Modifiers = SHIFT
UseableIn = GAME
End

CommandMap DECREASE_OBSERVER_NOTIFICATION_FONT
Key = KEY_MINUS
Transition = DOWN
Modifiers = SHIFT
UseableIn = GAME
End