Allow the client launcher to pass on command line arguments to the game it is launching.

[CCHyper]

Allow the client launcher to pass on command line arguments to the game it is launching. This would allow users to create a shortcut to the main client launcher executable, and hard code these to the ClientDefintions.ini.

For example;
TiberianSun.exe -GAME_ARGS=-DEVELOPER.

Vinifera implements a new "developer" feature to assist mod creators in their process, but mod creators need to keep modifying ExtraCommandLineParams= in ClientDefintions.ini to remove this before they push their update, sometimes this is not always done and results in an update being pushed where the end users enter the developer mode and another update is required to be pushed to revert this. Support for passing on custom arguments like this via the client launcher would allow mod creators to leave ExtraCommandLineParams= untouched, and then create a local shortcut for this to run the game in the developer mode.

Open to other suggestions as to how this could be implemented.

[LeuisKen]

I have a similar idea but more related to the player's perspective. #535
May be it's also okay for you to consider?

[SadPencil]

I have a similar idea but more related to the player's perspective. #535 May be it's also okay for you to consider?

After quickly reviewing your PR, #535 does not solve this issue but #547 does. This is because in most cases (except for game.exe and gamemd.exe in CnCNet YR) the client lanches the game executable via StartGameProcess().