* make tilejson's `name` be the same as the ID of the source (even if
aliased)
* `/catalog` will always show ID, but now it will hide the `name` if it
is the same as the `id`
* make `description` be the longer version, e.g. `public.table.column`
format - not guaranteed to be stable
* make `vector_layers` have the fields auto-discovered in the PG table
* preserve the order of the serialized json fields
Fixes#583
Compression middleware turned out to be hard to use for image cases - it
simply looks at the content-encoding, and if not set, tries to compress
if accepted by the client.
Instead, now individual routes are configured with either that
middleware, or for tiles, I decompress and optionally recompress if
applicable.
Now encoding is tracked separately from the tile content, making it
cleaner too. Plus lots of tests for mbtiles & pmtiles.
Fixes#577