Issue: More Customizeable URL Routing

Completed the DMs and controllers needed to save and parse custom routing. The rule list is fetched as described above, since the models for the various cache retrievers have been abstracted and instructed to create a database link if none already exists. Routing just needs to be implemented via a form field for each content type, but this should be considered part of the completion of the editors for those types.

Setup for custom page action routing should be handled as a separate feature since it will not be completed for Alpha 1.

Originally suggested for 3.0.4.

Implemented in 4.2.x. At the current time, we don't allow changes to the page actions, but we do allow the following:

- Admin defines which domains can be used for the wiki, and if any domains are used only by the wiki.
- Admin defines which paths, relative to a domain, can be used for the wiki, and if those paths are used only by the wiki.
- Admin defines which route-prefixes can be used for the wiki, and if those routes are used only by the wiki.
- Admin defines which route-prefixes can be used in combination with which paths.

- Admin defines a default path which applies to all content within an area.
- Admin defines which paths can be used as a custom path within an area.
- Admin defines a default path which applies to any content not within an area (index, certain feeds).

- User must have permission to customize URLs. If the user does not have permission, existing content will continue to use the existing URL. For new content, the default URL would be used.

- In the editor for a page, users specify a domain, path, and route-prefix respectively. Users can choose to have the URL relative to the area (or certain other parents) or not. Users can specify a custom title which is used only for the URL (without affecting the page's name). For example, a page named "This is a test" can have a custom URL such as "domain/path/route/Test-page" instead.

- Altering a custom URL after the fact will create a special kind of synonym even if the page's title was unchanged (this can be suppressed using the same mechanism as before). This prevents existing bookmarks, search engine listings, and direct links from suddenly breaking.

- Existing custom URLs that were created by plugins in VaultWiki 3.x are automatically converted so they continue to function normally.

If there is enough demand, we may revisit page-action customization in the future.