Add sortables and collection search #7

[m-mohr]

Related Issue(s): #7

Proposed Changes:

1. Add support for sortables based on OGC API - Features - Part 5: Schemas
2. Add the details about how to make sort available for collections / collection search.

All changes are purely additive, no changes to existing implementations are required unless sortables are implemented.

PR Checklist:

• This PR has no breaking changes.
• I have added my changes to the CHANGELOG or a CHANGELOG entry is not required.

[m-mohr]

@philvarner Any thoughts on this? Asking you specifically, because you are listed as owner of the extension.

[fmigneault]

Would it make sense to have a /collections/{id}/sortables to consider collection-specific sorting properties of returned STAC Items? Given that collections might contain very different things, the Catalog wide /sortables might not always be appropriate.

[m-mohr]

@fmigneault That's included, see https://github.com/stac-api-extensions/sort/pull/12/files#diff-b335630551682c19a781afebcf4d07bf978fb1f8ac04c6bf87428ed5106870f5R130

[fmigneault]

My bad. Misread the table alignment.