Remove Keybase integration (#17045)

app/controllers/api/proofs_controller.rb

...controllers/api/v1/accounts/identity_proofs_controller.rb

app/controllers/settings/identity_proofs_controller.rb

...controllers/well_known/keybase_proof_config_controller.rb

app/javascript/mastodon/actions/identity_proofs.js

...javascript/mastodon/features/account/components/header.js

...t/mastodon/features/account_timeline/components/header.js

.../features/account_timeline/containers/header_container.js

app/javascript/mastodon/features/account_timeline/index.js

app/javascript/mastodon/reducers/identity_proofs.js

app/javascript/mastodon/reducers/index.js

app/javascript/styles/mastodon/forms.scss

app/lib/activitypub/adapter.rb

app/lib/proof_provider.rb

app/lib/proof_provider/keybase.rb

app/lib/proof_provider/keybase/badge.rb

app/lib/proof_provider/keybase/config_serializer.rb

app/lib/proof_provider/keybase/serializer.rb

app/lib/proof_provider/keybase/verifier.rb

app/lib/proof_provider/keybase/worker.rb