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
* clean up reporting of the un-used config params - instead of printing,
collect them and print in one place if needed (allows testing too)
* remove `vector_layer` in catalog - too verbose, not needed - can be
received via tilejson for individual source
* clean up tests so that they all use the same config yaml
* NEW: support for #512 - pg table/function auto-discovery
* can filter schemas
* can use patterns like `{schema}.{table}.{column}` and
`{schema}.{function}`
* NEW: add `disable_bounds` bool flag to allow disabling of the bounds
computation
* reworked integration tests to use yaml
