Attempts to fix issue #114.

Avoids an extra SQL lookup on every request (a drop in the
ocean, but still).

Without this package PHP can't generate OpenSSL keys apparently.

Using what is hopefully the right format for the tx.allowed_request_content_type
configuration variable.

Only comment changes, illustrating the new defaults.

This reverts commit 9c69d4de.

This reverts commit 4acd8455.

It shouldn't be necessary in our setup, and it just makes keys
needlessly longer.

Seems like it might be needed by wp2pgpmail.

And disallow all requests that are not static content.

According to the docs in
https://httpd.apache.org/docs/current/rewrite/flags.html#flag_l using
[L] in an .htaccess context incurs the risk of infinite recursion,
which is exactly what we were seeing in production for non-existing
.php files. Use [END] instead.

Update the WP Multisite section according to
https://wordpress.org/support/article/htaccess/#wordpress-3-5-and-up