Document the distribution of GSHHS via auto-download on the server about gshhg-gmt

[maxrjones]

For this and GenericMappingTools/dcw-gmt#23, my preferred solution would be to add issue templates for releasing new versions of GSHHG and dcw respectively that includes a checklist of steps, including updating the version on the server. Then, one could open a 'Release gshhg X.X.X' issue that will track the necessary steps. I'll open pull requests to add these templates to the repositories.

[maxrjones]

My understanding is that we still use the self-hosted server in addition to GitHub releases or Zenodo for the gmt releases because certain package managers expect to find new releases there and we want to accommodate them. Is this the case too for these version-less geography/gshhg and geography/dcw directories? I am wondering why it is better to add the documentation for continuing this method of distribution rather than updating the GMT code to get gshhg and dcw from GitHub releases and perhaps abandoning /export/gmtserver/gmt/data/geography/, which would be less work for us long-term?

[PaulWessel]

I am OK with that solution as well. I think @seisman was the one who advocated for the server method (?), so will let him have a chance to comment first.

[seisman]

updating the GMT code to get gshhg and dcw from GitHub releases and perhaps abandoning /export/gmtserver/gmt/data/geography/

GitHub is partially blocked in China, so downloading a tarball from GitHub releases is slow and sometimes may fail for most Chinese users who don't have a VPN.