Introduced JDT Facade project

[LorenzoBettini]

For #3129

This is a possible JDT facade project I had in mind.

For the moment, it only includes #3189 but I was planning to confine there all, or most, of our usage of JDT internals.

However, I'd first start with reflection hacks.

I'd like to have some initial feedback @cdietrich @szarnekow

[github-actions]

Test Results

  6 460 files  ±0    6 460 suites  ±0   3h 8m 40s ⏱️ - 4m 15s
 43 242 tests ±0   42 658 ✅ ±0    584 💤 ±0   0 ❌ ±0 
170 307 runs   - 2  167 936 ✅ ±0  2 358 💤 ±0  13 ❌  - 2 

Results for commit c6989bb. ± Comparison against base commit 3f13054.

♻️ This comment has been updated with latest results.

[LorenzoBettini]

@cdietrich @szarnekow, could we merge this one so that the JDT Facade project is introduced, and then we or I can add other JDT internal calls and hacks to the project?