Add links to related tools

[callumrollo]

From the OceanGliders best practices discussion. We could link to useful tools for e.g. converting nasty glider manufacturer data to more usable formats.

@jbusecke suggests we add a ‘related’/‘compatible’ package section to the documentation

[callumrollo]

e.g. this Python package to import Slocum tabular ascii data files by John Kerfoot https://github.com/kerfoot/gdm

[dhruvbalwada]

Here is a list for Argo data: euroargodev/argopy#3 , maybe there will be some overlap

[soerenthomsen]

There is https://dbdreader.readthedocs.io / https://github.com/smerckel/dbdreader and https://github.com/smerckel/gliderflight by @smerckel

[callumrollo]

shameless plug I'm working on gliderpy, an ERDDAP data fetcher for glider data. I would love to be able to pipe the output from that straight into GliderTools