Create a new ContactList that will eventually fully replace PidginBuddyList

Create a new PidginContactList window and move the application actions to PidginApplication.

Testing Done:
* Verified menus are properly disabled while offline
* Verified menu items that require a protocol with chats enables the chat menu items as well as the room list menu items
* Verified that the menu items can become enabled while the menus are opened
* Verified that the application actions are activatable via dbus
* Verified that the plugin manager action was migrated successfully
* Verified that the account manager action was migrated successfully

Reviewed at https://reviews.imfreedom.org/r/174/