No page to allow proposing a new tag alias/implication

[ToksT]

In Danbooru 1, the New Tag Alias and New Tag Implication pages would allow a user to enter the From tag, To tag, and Reason, and automatically create a forum post proposing an alias/implication.

Currently, the pages are only for admins to create tag aliases. Separate pages for proposing them should exist.

Furthermore, the "New" link should be hidden from those below admin level, replaced with a "Propose" link or similar that leads to those pages.

As a minor side issue, the /tag_implications/new page wants you to be logged in as an admin just to view it, but the /tag_aliases/new allows anyone to view it, and only asks you to log in to click the "Create Tag Alias" button.

Related: #802