STAC harmonization changes

[pvretano]

Numerous changes listed in issue #178 to bring OARec and STAC into closer alignment.

Closes #178
Closes #231
Closes #232

[pvretano]

27-APR-2023: Discussion about why the time field is a top level field versus the STAC datatime property. The idea with the time member is, like geometry, to provide a fixed key for temporal filter as opposed to looking at stuff in the properties object which can be domain or community-of-interest specific. At the moment, there is no conflict between Records and STAC in this respect but there might be an unfortunately duplication on information if the temporal info exists both in the properties object using STAC properties and the time member in Records. Not ideal but no easy resolution.

[cnreediii]

@tomkralidis what does resolution mean in this context? Thnx

@cnreediii the resolution of the temporality of the data (hourly measurements [P1D], etc.)