### What problem does this PR solve?

Switching threading.Lock() to asyncio.Lock(), since threading.Lock() is
blocking.

### Type of change

- [x] Performance Improvement

### What problem does this PR solve?

Fix sandbox sandalone context error. #8307.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

Add sandbox FAQ. 

#7699 #7973 #8049 #8196 #8226.

### Type of change

- [x] Documentation Update
- [x] Refactoring

### What problem does this PR solve?

Change allocate_container_blocking Calculate Time by async time

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

### What problem does this PR solve?

Add code_executor_manager. #4977.

### Type of change

- [x] New Feature (non-breaking change which adds functionality)