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/file.go

@@ -315,7 +315,7 @@ func (a *App) findTeamIdForFilename(post *model.Post, id, filename string) strin
 }
 
 var fileMigrationLock sync.Mutex
-var oldFilenameMatchExp *regexp.Regexp = regexp.MustCompile(`^\/([a-z\d]{26})\/([a-z\d]{26})\/([a-z\d]{26})\/([^\/]+)$`)
+var oldFilenameMatchExp = regexp.MustCompile(`^\/([a-z\d]{26})\/([a-z\d]{26})\/([a-z\d]{26})\/([^\/]+)$`)
 
 // Parse the path from the Filename of the form /{channelID}/{userID}/{uid}/{nameWithExtension}
 func parseOldFilenames(filenames []string, channelID, userID string) [][]string {