ENH: Add POLAR boundaries

[aburrell]

Is your feature request related to a problem? Please describe.
I'm always frustrated when there's a time period where boundary observations have been made, but OCBpy doesn't include them.

Describe the solution you'd like
Add particle-precipitation corrected boundaries for the Polar satellite observations to OCBpy

Describe alternatives you've considered
Leave it alone.

Additional context
Got a dataset of Polar boundary identifications and and working on pairing them with Newell boundaries.