Deprecate `gofeatures` module

[unmultimedio]

We can deprecate gofeatures and fold it into wellknowntypes. cc @pkwarren @jhump

[unmultimedio]

The latest synced version of gofeatures already includes a buf.md with a deprecation notice, redirecting to the WKT modules instead. Eg: https://buf.build/protocolbuffers/gofeatures

[jhump]

@unmultimedio, does that mean we can now safely delete the gofeatures module from this repo (to stop it sync'ing any future versions)?

[unmultimedio]

@unmultimedio, does that mean we can now safely delete the gofeatures module from this repo (to stop it sync'ing any future versions)?

I need to first clean up some bits from the BSR's code, and then we can drop it from here 😄 . It's already commented out from the sync script, so it's not syncing new releases anyway.