Support Microsoft Planetary Browser STAC API

[cholmes]

I can add microsoft's STAC service at https://planetarycomputer.microsoft.com/api/stac/v1 to the api list, but when I hit search I get 'Network Error: [501] Not Implemented'.

It looks to be a STAC API 1.0.0-beta.1, with STAC core 1.0.0-beta.2, running https://github.com/stac-utils/stac-fastapi

[lossyrob]

Currently this API does not implement the queriables extension; this should be released in July.

Ideally this plugin can check the conformsTo links to understand what an API implements, and enable/disable features based on that (e.g. disable cloud cover if queriables is not implemented.