feat(github): add github integration

[ReenigneArcher]

Description

This PR aims to more tightly integrate GitHub with our discord bot.

Main features to add

1. Assign roles based on GitHub sponsorship status
2. Assign dev-user role based on GitHub account... (whether it exists, has contributed, or something along those lines)

TODO:

• Persist OAuth status?
• Periodically check GitHub user's for sponsor status, and add user to sponsor roles, or revoke accordingly
• Callback to public URL
• Possible to hide disocrd bot IP? Unlikely, I guess
• Improved SSL certs
• Update dockerfile
• Update readme/docs
• Add/update unit tests
  • Unit tests hang on unix due to async nonsense
  • Unit tests do not post comment even though tests pass (on Windows)
  • More test coverage
• Add GitHub username to user_info_commmand
• Add alternate authentication via GitHub directly instead of only Discord
• Update the ephemeral command once the authorization flow has finished, errored, or timed out
• Assign dev-user, contributor, etc. roles automatically

Screenshot

Issues Fixed or Closed

• Resolves Receive and process external webhooks #66

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components

[codecov]

Codecov Report

Attention: Patch coverage is 83.55856% with 73 lines in your changes missing coverage. Please review.

Project coverage is 67.06%. Comparing base (cb15726) to head (471be79).

Files with missing lines	Patch %	Lines
src/discord/cogs/github_commands.py	39.53%	26 Missing ⚠️
src/discord/tasks.py	84.48%	18 Missing ⚠️
src/__main__.py	0.00%	12 Missing ⚠️
src/discord/cogs/moderator_commands.py	16.66%	5 Missing ⚠️
src/common/webapp.py	96.66%	4 Missing ⚠️
src/discord/views.py	25.00%	3 Missing ⚠️
src/common/common.py	85.71%	1 Missing ⚠️
src/discord/bot.py	97.95%	1 Missing ⚠️
src/discord/cogs/base_commands.py	50.00%	1 Missing ⚠️
src/discord/cogs/fun_commands.py	50.00%	1 Missing ⚠️
... and 1 more

Additional details and impacted files

@@             Coverage Diff             @@
##           master     #368       +/-   ##
===========================================
+ Coverage   45.80%   67.06%   +21.26%     
===========================================
  Files          15       21        +6     
  Lines         786     1078      +292     
===========================================
+ Hits          360      723      +363     
+ Misses        426      355       -71     

Files with missing lines	Coverage Δ
src/common/crypto.py	100.00% <100.00%> (ø)
src/common/database.py	100.00% <100.00%> (ø)
src/common/globals.py	100.00% <100.00%> (ø)
src/common/sponsors.py	100.00% <100.00%> (ø)
src/common/time.py	100.00% <100.00%> (ø)
src/reddit/bot.py	80.39% <100.00%> (+0.13%)	⬆️
src/common/common.py	92.85% <85.71%> (ø)
src/discord/bot.py	92.39% <97.95%> (+28.92%)	⬆️
src/discord/cogs/base_commands.py	32.00% <50.00%> (ø)
src/discord/cogs/fun_commands.py	42.10% <50.00%> (ø)
... and 7 more

... and 1 file with indirect coverage changes