Automate create_plugin_registries

[evrose54]

Reviewer Checklist

• Required existing tests pass (ie full_test.sh, others as appropriate)
• Required unit tests added and pass for new/modified functionality
• NO REQUIRED integration tests (explain why not required)
• Required documentation added for new/modified functionality
• Required release notes added for new/modified functionality
• Required updates to other repos added for new/modified functionality

Related Issues

fixes #647
Correlated PR in data_fusion is required to fix a slowdown to data_fusion procflows which was introduced by this PR.

We can close the correlated PR if we decide to keep this PR as-is. A discussion needs to occur about the downstream impacts of defaulting, or not defaulting, to rebuilding the plugin registries on a plugin retrieval failure.

Testing Instructions

Run ./tests/integration_tests/full_test.sh

Summary

The command 'create_plugin_registries' has greatly improved the time it takes to
operate GeoIPS under the hood. This is because all plugins are no longer loaded into
memory, as we can now traverse a plugin registry to load the exact plugins we need
to, when we need them. Unfortuneately, this requires the user to run
'create_plugin_registries' anytime a new plugin has been added to one or more plugin
packages. We've been thinking for a long time of how to automate this process, and
this update does just that.

'create_plugin_registries' can now either be ran manually, or will attempt to be
done automatically by GeoIPS when a plugin is requested. If a user has no registries
in any of their plugin packages, then this is ran the first time get_plugin is
called when certain attributes of the associated interface are being initialized.

If the registries already exist, but a plugin is missing or seemingly out of sync,
then 'create_plugin_registries' will be ran, and get_plugin will be called again. If
the failure persists, then it is likely a problem on the user's end that they need
to fix before running GeoIPS. Now, users no longer have to run
'create_plugin_registries', unless they choose to do so manually.

File Updates:

added:
  - tests/unit_tests/plugins/test_get_plugin.py
modified:
  - geoips/commandline/geoips_test.py
  - geoips/interfaces/base.py
  - geoips/interfaces/module_based/output_checkers.py
  - geoips/interfaces/yaml_based/products.py

Output

from geoips.interfaces import readers

test_plg = readers.get_plugin("fake_plugin")

# OUTPUT

Running create_plugin_registries due to a missing plugin.
16_203926 create_plugin_registries.py:318  INTERACTIVE: Writing /local/home/evan/geoips/geoips_packages/geoips_clavrx/geoips_clavrx/registered_plugins.json
16_203927 create_plugin_registries.py:318  INTERACTIVE: Writing /local/home/evan/geoips/geoips_packages/data_fusion/data_fusion/registered_plugins.json
16_203927 create_plugin_registries.py:318  INTERACTIVE: Writing /local/home/evan/geoips/geoips_packages/recenter_tc/recenter_tc/registered_plugins.json
16_203927 create_plugin_registries.py:318  INTERACTIVE: Writing /local/home/evan/geoips/geoips_packages/geoips_plugin_example/geoips_plugin_example/registered_plugins.json
16_203928 create_plugin_registries.py:820  INTERACTIVE: Skipping module 'interp_scipy' from 'geoips', interface_name is 'None'
16_203928 create_plugin_registries.py:820  INTERACTIVE: Skipping module 'boxdefinitions' from 'geoips', interface_name is 'None'
16_203928 create_plugin_registries.py:820  INTERACTIVE: Skipping module 'interp_pyresample' from 'geoips', interface_name is 'None'
16_203928 create_plugin_registries.py:820  INTERACTIVE: Skipping module 'geostationary_geolocation' from 'geoips', interface_name is 'None'
16_203928 create_plugin_registries.py:820  INTERACTIVE: Skipping module 'hrit_reader' from 'geoips', interface_name is 'None'
16_203928 create_plugin_registries.py:820  INTERACTIVE: Skipping module 'remss_reader' from 'geoips', interface_name is 'None'
16_203928 create_plugin_registries.py:820  INTERACTIVE: Skipping module 'tc_file_naming' from 'geoips', interface_name is 'None'
16_203928 create_plugin_registries.py:318  INTERACTIVE: Writing /local/home/evan/geoips/geoips_packages/geoips/geoips/registered_plugins.json

PluginError: Plugin 'fake_plugin', from interface 'readers' appears to not exist.
Create plugin, then call create_plugin_registries?

[jsolbrig]

This should have a CLI flag added to allow turning on automatic registry creation.