Fix Multiprocessing Shenanigans

[TheTechromancer]

Addresses #1904.

This PR introduces better PID tracking to avoid multiprocessing mishaps, and adds a test to make sure BBOT can be used inside a fastapi endpoint.

[codecov]

Codecov Report

Attention: Patch coverage is 86.46617% with 18 lines in your changes missing coverage. Please review.

Project coverage is 93%. Comparing base (09f7ec3) to head (53e9084).
Report is 30 commits behind head on dev.

Files with missing lines	Patch %	Lines
bbot/core/multiprocess.py	85%	6 Missing ⚠️
bbot/core/helpers/command.py	0%	4 Missing ⚠️
bbot/test/fastapi_test.py	67%	4 Missing ⚠️
bbot/core/core.py	75%	3 Missing ⚠️
bbot/test/test_step_1/test_bbot_fastapi.py	99%	1 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff           @@
##             dev   #1955    +/-   ##
======================================
- Coverage     93%     93%    -0%     
======================================
  Files        363     366     +3     
  Lines      27845   27958   +113     
======================================
+ Hits       25668   25757    +89     
- Misses      2177    2201    +24     

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[aconite33]

Approved. All tests passed.