mysql already has its socket path hardcoded to to
/run/mysqld/mysqld.sock.
There's not much value in making the pidDir configurable, which also
points to /run/mysqld by default.
We only seem to use `services.mysql.pidDir` in the wordpress startup
script, to wait for mysql to boot up, but we can also simply wait on the
(hardcoded) socket location too.
A much nicer way to accomplish that would be to properly describe a
dependency on mysqld.service. This however is not easily doable, due to
how the apache-httpd module was designed.
Symlinking works for most plugins and themes, but Avada, for instance, fails to
understand the symlink, causing its file path stripping to fail. This results in
requests that look like:
https://example.com/wp-content//nix/store/...plugin/path/some-file.js
Since hard linking directories is not allowed, copying is the next best thing.
* Moved the wordpress sources derivation to the attribute pkgs.wordpress. This
makes it easier to override.
* Also introduce the `package` option for the wordpress virtual host config which
defaults to pkgs.wordpress.
* Also fixed the test in nixos/tests/wordpress.nix.
