Refactoring CMakeLists.txt

• Changing SDL to SDL2
• Adding main menu
• Adding pause menu
• Adding context menu
• Creating universal CMakeLists.txt

changed milestone to %Implementation der UI und Game-Struktur

added In Progress label

requested review from @david.maul

assigned to @david.hermann

added 39 commits

• 45baa9dc...69cab54b - 38 commits from branch main
• 2a1d2063 - Merge branch 'main' into 'ui'

Compare with previous version

merged

mentioned in commit 16795c19