Added pacific power meters to Meter class and API

[s-egge]

Run the backend locally and go to http://localhost:3000/allbuildings to see the addition of pacificPowerID in the Meter class:

[s-egge]

Updated Unit Tests

Previous tests failed due to the new pacific_power_id field. I've added this field to the test database, and all inserted meter data has the field as null since none of them are Pacific Power Meters.

[solderq35]

Looks good to me. For the backend/tests/assertedData/meters_insert.sql file, I wasn't sure if NULL vs null mattered, but I tested both in SQL workbench and capitalization doesn't seem to matter, so it's all good.