Bands RFC #1213

[m-mohr]

Related Issue(s): #1213

Proposed Changes:

• bands is a new field in common metadata to replace eo:bands and raster:bands (#1213)
• The fields data_type, nodata, statistics and unit have been added to common metadata (#1213)

This PR needs to wait for the EO and Raster Extension PRs.

ToDo:

• infinity, NaN in band statistics stac-extensions/raster#40
• Draft version 2.0 of eo:bands stac-extensions/eo#27

PR Checklist:

• This PR is made against the dev branch (all proposed changes except releases should be against dev, not master).
• This PR has no breaking changes.
• I have added my changes to the CHANGELOG
  or a CHANGELOG entry is not required.
• This PR affects the STAC API spec,
  and I have opened issue/PR #XXX to track the change.

[emmanuelmathot]

Concerning the last commit, there is no way to make suggestions on unchanged file so I simply committed it. Let me know.

[m-mohr]

We should discuss whether we want to explicitly disallow to use of "bands" for single-band use-cases where instead people must provide the properties at the asset/item properties level directly.

[emmanuelmathot]

We should discuss whether we want to explicitly disallow to use of "bands" for single-band use-cases where instead people must provide the properties at the asset/item properties level directly.

I vote +1 for disallowing unique band