Search Console redirects

[samglover]

This PR addresses over 2,300 404s resulting from the new Court Forms Online, as reported by Google Search Console. Apparently the old website included PDF templates in the /forms/ and /pdfs/ directory. This PR will redirect those URLs to /forms (only for URLs that include .pdf).

It also includes a regex for URLs containing /slack_archive/, and redirects them to the documentation website.

And there are a few specific (non-regex) redirects.

I also removed the line that disabled image optimization, as optimized images seem like a good thing. It works fine locally, so it seems worth trying.

[nonprofittechy]

I think we should check in with @colarusso on this--most of the broken links seem to be from the form explorer page, and maybe we want to restore that content.

[samglover]

Since the plan is to move the Form Explorer CSV and files, I'll hold off and update this PR when that has happened.

[samglover]

I've updated the redirects so that Form Explorer PDF files like https://courtformsonline.org/forms/6b4ebd487f82f387512ac20da28803db.pdf will redirect to https://formexplorer.suffolklitlab.org/forms/6b4ebd487f82f387512ac20da28803db.pdf. I've also updated the redirect for the Form Explorer CSV.

I removed the other redirects. I'd like to wait a couple more weeks for Google's search index to "settle" before I redirect specific URLs. I've already seen some 404s disappear as Google updates its index, and there's no need to clutter the config file with unnecessary redirects.