Issue #36 automatic game menu

will close #36

changes:

in the project config I disabled blender support for now to prevent a warning. (no blender path was added)
added a games_manager that manages configs and game detection
refactor selection to dynamically create game buttons
- the scene has also now a slightly different structure to react on different number of buttons
all folders under scenes/games will automatically create a game button
- folder names that start with underscore "_" will be ignored (for work in progress games)
when a game_icon.png is provided it will be used for the game button
if a game.cfg is there it will use that, if not the game name will be the folder name
- name: (String) name for the game
- order: (int) a order number to place the button where you want
- every unknown config will be passed an could be used for other things
- as an example the cannon game is fully configured and has a new (dummy) icon

MrEliptik / godot_twitch_games