Optional Time Granularity for Time Dimensions in the Where Filter

[plypaul]

Resolves #175

Description

Please see the associated issue for more details.

Checklist

• [x] I have read the contributing guide and understand what's expected of me
• [x] I have signed the CLA
• [x] This PR includes tests, or tests are not required/relevant for this PR
• [x] I have run changie new to create a changelog entry