Release 11.6.5.3

[krzychu124]

Because of mess with already merged stuff and incompatibilities with other mods it will be released to Test and Stable at the same time to bring back ability to swap between Stable <-> Test

Cherry-picked commits to build new release version, nothing to review.

• [x] What's new.txt (Test) needs to be updated to include changes between 11.6.5.2-hotfix-1 (what's already in the commits)
• [x] What's new.txt - short recap for Stable changelog - changes between 11.6.5.2-hotfix-1 and current Stable 11.6.4.8
• [x] Cherry-picked API changes from #1577
• [x] Readme.md/Changelog.md update?

Minor fixes after final tests:

• [x] Fixed InvalidCastException under certain condition prevented save/load of options, could mistakenly show message about path-finding update - airplane despawn
• [x] Fixed missing scrollbar at Keybinds tab
• [x] Corrected scope of DLS slider availability, improved visuals of read-only dropdown and slider
• [x] Fixed issue with misleading warning when changing Road Signs theme in main menu (no need to warn - GlobalConfig option)

ok... a lot of changes, actually https://github.com/CitiesSkylinesMods/TMPE/compare/11.6.4.8...release/11.6.5.3

Link for testing 11.6.5.3 Stable.zip

[krzychu124]

There is a conflict... I'll fix it after release because I need last commit without changes from master to create a tag

[kianzarrin]

LGTM