Add CMIP5 Temperature and Precipitation items

[cstephen]

This draft PR implements the CMIP5 Temperature and Precipitation items at maximum feasible chart granularity, meaning:

• Precipitation charts are based on annual values (not pre-summarized eras), but "bucketized" into decadal min/mean/max bars similar to many other ARDAC items. The mins and maxes are based on the min/max annual means.
• Temperature charts are based on monthly values (month selected from the dropdown) and bucketized into annual min/mean/max bars for the month. This works slightly differently from the Precipitation charts, however, because the min/max values in the chart are based on actual monthly mins and maxes, not just the min/max mean for the year. See the /tas2km/point API documentation/output for more info.

To test, point to (uncached) Apollo for now because not all coverages are available on Zeus at the moment:

export RASDAMAN_URL=https://apollo.snap.uaf.edu/rasdaman/ows
npm run dev

You'll notice that the temperature maps are janky/distorted, but when we have run into this problem in the past, it was solved simply by hosting the coverage from Zeus instead of Apollo. So I expect this to fix itself when we ingest the needed coverages into Zeus. The needed Zeus coverages are:

• annual_precip_totals_mm
• tas_2km_historical

I'm keeping this PR in draft mode until then.