Document MBTiles schema as a separate book page

[nyurik]

We currently have a single tools page that contains both the description of the mbtiles tool, as well as some documentation for the mbtiles schema extensions we support (e.g. hash validation and the well defined normalized/non-normalized/... formats).

I think we should split-up the tools page - to create a documentation section for mbtiles, that has a page documenting schema variants, the hashing capabilities, and another page documenting some capabilities of the mbtiles tools

[sharkAndshark]

Is it like? @nyurik

- [MBTiles](50-mbtiles.md)
  - [Supported schemas](51-supported-schemas.md)
  - [Tools](52-tools.md)

[nyurik]

I think tools (CLI) docs should go first, so maybe name them 51-mbtiles-cli, 52-mbtiles-schemas ? But yes, that's the general approach, thx!