So we can use it to write a plugin for embedding React components within
TT.

Instead of trying to delete all the problematic keys that contain CODE
references or circular data structures.

Some components don't need context.

We don't want the component path to include the query parameters.

It won't send errors if the DSN is falsey, but not running it will cause
exceptions to be thrown later.

This better allows us to provide mostly the same API.

Now that we have a plugin for embedding React components within TT,
reading & writing data to Redis for every call to that plugin has become
prohibitively slow. Use a UNIX socket to communicate with the renderer
instead.

The template-renderer Dockerfile has been removed, and a renderer
service has been added to the existing website container. This is
simpler and probably more correct, since MBS can only communicate with a
renderer on the same host, and it doesn't make sense to communicate with
it as a standalone service, only through the website.

These variables aren't even in the environment anymore, so this code
didn't work. It was likely broken sometime around
49e48ce.

The effect of this function is to allow for easier development, so
JavaScript files/templates can be edited without having to restart the
renderer (otherwise, the modules and their associated definitions would
be cached).

This function was previously called at the start of each request to the
renderer. But given that we can now emebed React components within TT,
it's incredibly slow to call this for every component (which corresponds
to what used to be a "request"). So, we now only call this function at
the beginning of each request cycle.

Needs to be stringified (React can't output objects).

Note: Having Form::Search::Search and Form::User::Login extend
MusicBrainz::Server::Form breaks those forms in silent and strange ways,
so I've moved TO_JSON to a separate role for now.

At least not without a special flag.

compile_resources.sh needs those env variables.