DEP: removed support for dmsp_ssj_boundaries

[aburrell]

Description

Removed support for old package `dmsp_ssj_boundaries. Fixes #129 and #135.

Type of change

Please delete options that are not relevant.

• Breaking change (fix or feature that would cause existing functionality
  to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Unit tests.

import ocbpy

# Fetch the zenodo archive for all dates and satellites.
ocbpy.boundaries.dmsp_ssj_files.fetch_ssj_boundary_files()

Test Configuration

• Operating system: OS X Big Sur
• Version number: Python 3.9
• Any details about your local setup that are relevant: develop branch of pysat

Checklist:

• Make sure you are merging into the develop (not main) branch
• My commits are formatted appropriately (following the SciPy/NumPy style)
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• Add a note to Changelog.rst, summarising the changes
• Add yourself to AUTHORS.rst and .zenodo.json

[coveralls]

coverage: 99.775% (+7.6%) from 92.213%
when pulling 5c17a34 on ssj_dep
into 6fe61d2 on develop.