feat(federation_domain_whitelist): support wildcards

[lukaslihotzki-f]

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[codecov]

Codecov Report

❌ Patch coverage is 47.82609% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.06%. Comparing base (9005cfc) to head (f34d155).

Files with missing lines	Patch %	Lines
synapse/config/federation.py	53.33%	5 Missing and 2 partials ⚠️
synapse/media/media_repository.py	33.33%	0 Missing and 2 partials ⚠️
synapse/federation/transport/server/_base.py	50.00%	0 Missing and 1 partial ⚠️
synapse/http/matrixfederationclient.py	0.00%	0 Missing and 1 partial ⚠️
synapse/rest/key/v2/remote_key_resource.py	50.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #289      +/-   ##
==========================================
- Coverage   81.07%   81.06%   -0.02%     
==========================================
  Files         509      509              
  Lines       73447    73459      +12     
  Branches    11124    11128       +4     
==========================================
+ Hits        59546    59548       +2     
- Misses      10588    10596       +8     
- Partials     3313     3315       +2     

Files with missing lines	Coverage Δ
synapse/federation/transport/server/_base.py	75.64% <50.00%> (ø)
synapse/http/matrixfederationclient.py	83.22% <0.00%> (-0.21%)	⬇️
synapse/rest/key/v2/remote_key_resource.py	82.95% <50.00%> (ø)
synapse/media/media_repository.py	75.57% <33.33%> (ø)
synapse/config/federation.py	82.22% <53.33%> (-11.72%)	⬇️

... and 3 files with indirect coverage changes

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[jason-famedly]

This will need a few more tests, at the very least. Need to check the wildcard behavior does not include the naked bare domain. So if *.example.com is in the allow list, example.com is successfully rejected and etc.

I wonder if this would be better served with a regex solution? Perhaps with an in-memory cache to assist long term avoiding re-processing the same server name repeatedly. Even if we keep the existing parsing solution, this may be worth the effort. 🤔 Needs thought

Prior (unfinished) art: matrix-org/synapse#13424

Upstream issues for this:

• federation_domain_whitelist wildcard support matrix-org/synapse#7346
• federation_domain_whitelist wildcard support element-hq/synapse#7346

I have no opinion on if it should be upstreamed or not