Allow additions to ignore list even while unremovable users present

[dfsm]

• Function addUserToIgnoreList updated to take a userid and make POST to member2.php using parameters appropriate for the Profile (member.php) page.
• Fixed context menu to say "Ignore/Unignore user" conditionally
• Updated IgnoreListChangeScrapeResult.swift to add a success message produced by the forums. There's different text on the response page while adding an ignored user via profile vs ignore list

See: https://forums.somethingawful.com/showthread.php?threadid=3910071&pagenumber=104#post528132223

Tested:

• Adding user to ignore list: OK
• Removing user from ignore list (which uses the same method as before): OK
• Adding a mod to the ignore list: Error as expected