Auth Proxy: encoding of non-ASCII headers (#44797)

* Decode auth proxy headers using URL encoding

* Header encoding configuration via settings file

* Rename configuration setting to headers_encoded

* Quoted-printable encoding

* Tests for AuthProxy

* Fix encoding name

* Remove authproxy init

pkg/setting/setting.go

@@ -306,6 +306,7 @@ type Cfg struct {
 	AuthProxyEnableLoginToken bool
 	AuthProxyWhitelist        string
 	AuthProxyHeaders          map[string]string
+	AuthProxyHeadersEncoded   bool
 	AuthProxySyncTTL          int
 
 	// OAuth
@@ -1317,6 +1318,8 @@ func readAuthSettings(iniFile *ini.File, cfg *Cfg) (err error) {
 		}
 	}
 
+	cfg.AuthProxyHeadersEncoded = authProxy.Key("headers_encoded").MustBool(false)
+
 	return nil
 }