Randomized game mode feature

[SadPencil]

This PR introduces randomness to game modes. Apart from original map code, it can now randomly select and insert some map codes. The following example defines a random game mode, where when game starts, 2 files from RNG1.ini, RNG2.ini, RNG3.ini files will be randomly loaded

[A Random Game Mode]
UIName=A Random Game Mode
MapCodeININame=A Random Game Mode-Base.ini
RandomizedMapCodeININames=RNG1.ini,RNG2.ini,RNG3.ini
RandomizedMapCodesCount=2

[github-actions[bot]]

Nightly build for this pull request:

• artifacts-YR.zip
• artifacts-Ares.zip
• artifacts-TS.zip This comment is automatic and is meant to allow guests to get latest automatic builds without registering. It is updated on every successful build.