Upgrade Theia to 1.43.1 and GLSP to 2.0.0

[martin-fleck-at]

Upgrade Theia to 1.43.1:

• Use Node webpack configuration for Electron for smaller package
• Adapt start script to use the new backend entry point

Upgrade GLSP to 2.0.0:

• Re-use Json-based command/operation API in GLSP server
• Adapt to new diagram configuration in GLSP client
• Remove unused CrossModelUpdateClientOperationHandler

Bonus: Fix issue with wrong updates in model service and undo/redo

[github-actions[bot]]

Test Results

    3 files  ±0    30 suites  ±0   1m 41s :stopwatch: +23s   68 tests ±0    68 :heavy_check_mark: ±0  0 :zzz: ±0  0 :x: ±0  207 runs  ±0  207 :heavy_check_mark: ±0  0 :zzz: ±0  0 :x: ±0 

Results for commit bf517eeb. ± Comparison against base commit ce0fa565.