Standardize endpoint arg names and formats

[nmdefries]

• Integer-type geo codes (e.g. fips) should be able to be passed as integers to geo_values, like dates can
• make pub_delphi support a range of epiweeks; currently only takes one epiweek date at a time. This could also be changed in delphi-epidata
• don't like that endpoints don't all have the same args (although I can see why). Might be nice to unify them more, though. e.g. pub_ecdc_ili uses epiweeks when it could just use time_values
  • Call all date params that take epiweeks epiweeks, and all days dates.

[brookslogan]

Personally, I don't think FIPS should be allowed to be passed as an integer, since leading zeros are considered part of the code. But for other integer codes where this isn't the case this would make sense.