Improve documentation about Tile Publishing

[doublebyte1]

Recently, new functionality regarding tile metadata formats was added, but that is not yet reflected on the documentation.

Describe the solution you'd like
Explain what are the tile metadata formats supported, for now. We could create table that shows the formats supported per provided, similar to this.

Describe alternatives you've considered
Leaving the tile metadata undocumented.

Additional context
https://github.com/geopython/pygeoapi/blob/master/docs/source/data-publishing/ogcapi-tiles.rst

[doublebyte1]

Fixed by #1552 and #1566