Reverse proxy authentication support (#1152)

* feat(auth): reverse proxy authentication support - #176

* address PR remarks

* Fix redaction of UI appConfig

Co-authored-by: Deluan <deluan@navidrome.org>

conf/configuration.go

@@ -50,6 +50,8 @@ type configOptions struct {
 	EnableLogRedacting     bool
 	AuthRequestLimit       int
 	AuthWindowLength       time.Duration
+	ReverseProxyUserHeader string
+	ReverseProxyWhitelist  string
 
 	Scanner scannerOptions
 
@@ -201,6 +203,8 @@ func init() {
 	viper.SetDefault("authrequestlimit", 5)
 	viper.SetDefault("authwindowlength", 20*time.Second)
 
+	viper.SetDefault("reverseproxyuserheader", "Remote-User")
+
 	viper.SetDefault("scanner.extractor", "taglib")
 	viper.SetDefault("agents", "lastfm,spotify")
 	viper.SetDefault("lastfm.enabled", true)