Map GCReW met to GCW-W

[bpbond]

This PR adds metadata needed to map GCReW met data into the GCW-W L1 data. @wilsonsj100 I would appreciate your careful eyes on this to make sure sensible and intuitive.

We are mapping

• wx_gcrew_rain15 <-----
• wx_tempavg15
• wx_rh15
• wx_vappress15
• wx_vpd15 <-----
• wx_svp15 <-----
• wx_barpress15
• wx_slr_fd15
• wx_slr_tf15
• wx_par_den15
• wx_par_tot15
• wx_winddir15
• wx_maxws15
• wx_svp15 <-----
• wx_windspeed15

These are all the GCReW met outputs that map cleanly to COMPASS-FME met variables. There are three (wx_vpd15, wx_svp15, and wx_svp15) that do NOT appear at other synoptic sites but seemed useful so I included them.

There also is wx_gcrew_rain15. This is the rain output from GCReW met and is in cm, whereas the COMPASS sites' outputs are in mm. As a result, we send it to a NEW variable with a very distinctive name and you'll need to handle it specially.

The GCW metadata file now includes an explicit warning about this:

[bpbond]

GCW_W_20230308-20230322_L1_v1-0.csv

[bpbond]

Necessary for #158 but I need access to GCReW met raw data before closing that

[bpbond]

Feedback still and always welcome @wilsonsj100 , but I want to merge this to easily proceed with other things.