Portscanner Rework

[TheTechromancer]

This PR simplifies the port scanner situation in BBOT by deleting nmap and replacing it with a brand-new masscan implementation, augmented to handle hostnames.

This accomplishes a few things:

• helps relieve some of the confusion around there being two port scanners
• better performance (masscan is much faster than nmap)

TODO:

• Does masscan work with IPv6? (answer: YES)
  • localhost? Multiple interfaces? (answer: NO, but meh)
• Handle IPv6 abort

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 81.18280% with 35 lines in your changes are missing coverage. Please review.

Project coverage is 92%. Comparing base (a22cb9b) to head (b9c2e23).

Files	Patch %	Lines
bbot/modules/portscan.py	80%	32 Missing ⚠️
...step_2/module_tests/test_module_asset_inventory.py	86%	2 Missing ⚠️
bbot/modules/internal/speculate.py	0%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           bbot-2.0   #1375    +/-   ##
=========================================
+ Coverage        92%     92%    +1%     
=========================================
  Files           343     340     -3     
  Lines         23236   23048   -188     
=========================================
- Hits          21316   21156   -160     
+ Misses         1920    1892    -28     

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