Add readable URL slugs to Tag pages

[jimchamp]

Closes #9779

Adds a readable slug to Tag URLs. The slug is created from the Tag's name property.

Ensures that both types of edit requests are processed by the same handler (e.g. /tags/OL1T/magic/edit and /tags/OL1T/magic?m=edit).

Technical

Testing

While logged in as a super-librarian, test the following:

1. Paste a Tag URL in your browser's address bar. If the URL has a readable slug, remove it. Press enter to navigate to the view. Expect the URL to be rewritten to include a slug.
2. The "Edit" buttons on Tag views use the ?m=edit URLs. Ensure that you are redirected to a /tags/{tag_olid}/{slug}/edit page when this is clicked.
3. If a Tag is linked to a subject, that subject page's "Edit" button will take the patron to a /tags/{tag_olid}/{slug}/edit edit page. Ensure that the edit page is reachable when "Edit" is pressed. Important: Legacy subject to subject Tag linkage is buggy today. To avoid issues while testing, pick a subject-type subject that has no special characters in the subject name.

Screenshot

Stakeholders