Additional date/time data type inference for stats

[jqnatividad]

Right now, stats correctly infers the Date data type for these date formats.

We need to differentiate the Date subformats however into additional date data types:

• date (e.g. yyyy-mm-dd)
• date-time (e.g. yyyy-mm-dd hh:mm:ss UTC)
• time (e.g. hh:mm:ss UTC)

Doing so will not only improve the output of stats, it will also allow schema to properly create jsonschemas that validate can use to check for date/time fields in a performant, standards-compliant manner.