figures.py: ssh data functions

[douglatornell]

Original report by Nancy Soontiens (Bitbucket: nsoontiens, ).

---

I have some notebooks that I periodically run through to compare nowcast ssh with observations. They make use of functions:

load_archived_observations()
dateparse_archive_obs()
get_NOAA_wlevels()
get_NOAA_tides()
dateparse_NOAA()

I can see these being useful outside of the nowcast package or nowcast comparisons. Even just to get observed water levels over a time period.

Perhaps they can move to data_tools?