Set up observatory metadata load script

Similar to https://code.usgs.gov/ghsc/geomag/geomag-algorithms/-/blob/master/test_metadata.py .

Add theodolite, electronics, pier corrections, etc reference for all observatories (test observatories not needed):

• pull reference information from web absolutes where possible

• reference information for residual method observatories from Bill

• documentation of observatory metadata format

• script with reference metadata