This can't be imported at the top-level on the server, since jquery-ui
needs a window to exist.

$c->json has allow_blessed and convert_blessed enabled, so we can now
serialize entities that contain blessed objects like cover art.

The basic idea was that CDStubTOC modeled cdtoc_raw, and CDStub modeled
release_raw. But there's no clear reason why these are separate models,
since the tables have a 1:1 mapping (I'm not actually sure why they're
separate tables). You can't submit a CD stub without a disc ID. So these
models only serve to make the code confusing as to when you should
expect which entity.

For example, the CDStub entity class previously had discid and
track_count properties as shortcuts for the indexed search, which didn't
construct a full CDStubTOC in `schema_fixup`. These shortcuts made it
unclear when, for example, $cdstubtoc->discid was defined as opposed to
$cdstubtoc->cdstub->discid, or if $cdstubtoc->cdstub could always be
expected to be loaded.

The component uses different (and probably harder to translate) strings
than the expiration_time TT macro, and wraps the result in bracketed,
which the macro didn't do.

This commit also renames the component to ExpirationTime to match the TT
macro, which makes more sense.

This encompasses the edit page sidebar.

For hydrated components that take an entity prop, we were serializing
the entire entity (potentially including a giant list of relationships,
mediums, etc.) even though we only needed a few bits of data from it
(such as the entity type and gid).