The previous commit prematurely removed the socialcoop.meet.coop
registration form. This commit brings it back, along with the machinery
to ensure that users are logged in at social.coop before they can view
and/or submit the form.

Remove all wiki functionality (and metalsmith) in favor of serving up
the registration form as a static HTML page. The email templates from
https://git.coop/social.coop/general have been moved to the `templates`
directory.

Fixes #3

@ntnsndr in Matrix suggested that Welcome would be more friendly than
Home: https://matrix.to/#/!UqqWnMulCJMGobLvod:matrix.org/$ttyQ0fW66jgsgbxVvtKYMXwKTNe6PXafmo7_JV8ud5M?via=matrix.org&via=beeper.com

Since the page titles are currently derived from the Wiki file name, the
function has a special case for `home.md`.

... and fix logo url to point at wiki

Wiki header changes

See merge request social.coop/tech/wiki.social.coop!7

These changes were specified over in:

https://git.coop/social.coop/tech/wiki.social.coop/-/issues/2

Remove blog link from menu

See merge request social.coop/tech/wiki.social.coop!6

@ntnsndr in [social.coop tech
chat](https://matrix.to/#/!akkaZImONyQWKswVdt:matrix.org/$166838461578341rKyZr:matrix.org?via=matrix.org&via=autonomic.zone&via=pub.solar):
> Also, there is one blog post on the wiki. Can someone remove the
> "blog" from the menu? I'm not sure how to do that.

Document how wiki content updates propagate

See merge request social.coop/tech/wiki.social.coop!5

        i don't know why or how, but there were journalctl entries for
        an error in which .trim() was being called on an undefined
        value, on (old) line 144 where linkify() was being called.

        now we're catching and logging these cases, at least.

Add readme

See merge request social.coop/tech/wiki.social.coop!4

This makes it easier for community WG members to click

Use seperate path to handle oauth callback

See merge request social.coop/tech/wiki.social.coop!3

This fixes an issue where you'd be taken to an error screen if you
refreshed a restricted page while you had a then-invalidated code in
your url params

Add mastodon oauth for meet.coop-registration-form

See merge request social.coop/tech/wiki.social.coop!2

also add npm scripts for local dev

So it can be used for initial deploys or manual builds.
Otherwise it only builds via the incoming webhook.

This just checks there is a schema and it is a known valid version.

We're going to skip all but this step shortly, when processing honeypot trips.

Includes vulnerability audit fixes.