MM-52532: Fix golangci warnings (#23709)

https://mattermost.atlassian.net/browse/MM-52532

- Replace golint with revive
- Add makezero linter
- Fix all the required linter failures

Some issues in enterprise and public modules
are yet to be fixed. We send this to expediate things.

server/channels/app/plugin_public_keys.go

@@ -3,7 +3,7 @@
 
 package app
 
-var mattermostPluginPublicKey []byte = []byte(`-----BEGIN PGP PUBLIC KEY BLOCK-----
+var mattermostPluginPublicKey = []byte(`-----BEGIN PGP PUBLIC KEY BLOCK-----
 
 mQINBF3YTiEBEACgkhnZ5+xylKZhLVj193b6d/rSQuCU/zwWeZJnqyR8wRsPotXO
 CMXOUM9bTTaGfItCP9KlPPcyrshNEIgqcqhB6TSKkWSyrV5XS95Opd9Esbjw1VZq