Add a command to persist workbench state

[mickaelistria]

Fixes #3398

This command can be tried the following way:

Base

0. Start an IDE with this patch
1. Close some views
2. Kill the IDE (brutally, not with the nice "exit" button)
3. Restart: ❌ Closed views are here again

Diff

0. Start an IDE with this patch
1. Close some views
2. Ctrl+3 > "Persist workbench state"
3. Kill the IDE (brutally, not with the nice "exit" button)
4. Restart: ✔️ Closed views are not there

[github-actions]

Test Results

 3 018 files  ±0   3 018 suites  ±0   2h 21m 53s ⏱️ + 5m 4s
 8 226 tests ±0   7 977 ✅ ±0  249 💤 ±0  0 ❌ ±0 
23 598 runs  ±0  22 804 ✅ ±0  794 💤 ±0  0 ❌ ±0 

Results for commit ed34d7e. ± Comparison against base commit cbf687d.

♻️ This comment has been updated with latest results.

[BeckerWdf]

I think this is a nice an pragmatic addition