Add/store MetricsAndCovariates site-scale attributes in wb database

[volkcj]

There is a site-level set of attributes that used to be available in cm.org export databases but has been disabled. These attributes are 'generally available attributes' that have been pulled from various geospatial data sources and used to be available to crews in the ProgramMeasurements.mdb and ProgramMetrics.mdb, but has recently been removed.

Examples of the attributes are strahler order, drainage area and COMID.

I haven't checked to see if these are in the api, but it might be worth just carrying these as a static table in the workbench that aren't attached to cm.org (I can describe later)