Add public settings endpoint

shared/models/plugins/public-server.setting.ts

@@ -0,0 +1,3 @@
+export interface PublicServerSetting {
+  publicSettings: { [ name: string ]: string }
+}

shared/models/plugins/register-server-setting.model.ts

@@ -2,9 +2,15 @@ export interface RegisterServerSettingOptions {
   name: string
   label: string
   type: 'input'
+
+  // If the setting is not private, anyone can view its value
+  // Mainly used by the PeerTube client to get admin config
+  private: boolean
+
+  // Default setting value
   default?: string
 }
 
 export interface RegisteredServerSettings {
-  settings: RegisterServerSettingOptions[]
+  registeredSettings: RegisterServerSettingOptions[]
 }