Add HLS metadata to STAC

[waltersdan]

It would be helpful if more metadata for HLS images was included in the HLS STAC properties. Currently, the only metadata are eo:cloud_cover and the acquisition time. The remaining metadata for each image are available through the 'metadata' asset, but this requires a get() call for each image. This can be really slow when repeated hundreds of times (once for each image in a query). If the metadata were in the STAC item itself, then when using e.g., stackstack.stack(), all the metadata would be available in an xarray object and fast to access. In particular, it would be useful to have the original product ID which contains the satellite (e.g., Landsat-8 vs -9) and relative orbit number.

[william-valencia]

https://bugs.earthdata.nasa.gov/browse/CMR-10211 created to track this request.