refactor: small improvements and clean up (#3423)

* refactor: replace custom map functions with slice.Map

* refactor: extract StringerValue function

* refactor: removed unnecessary if

* chore: removed invalid comment

* refactor: replace more map functions

* chore: fix FFmpeg typo

server/initial_setup.go

@@ -83,7 +83,7 @@ func createJWTSecret(ds model.DataStore) error {
 	return err
 }
 
-func checkFfmpegInstallation() {
+func checkFFmpegInstallation() {
 	f := ffmpeg.New()
 	_, err := f.CmdPath()
 	if err == nil {