Purge non-essential management commands

[scottx611x]

• Specific code commit: 37306a0

Currently we have a few management commands that we have found to not be needed anymore:

• @jmarx Could you add the ones you wrote down during our meeting today below?

There are also Management commands whose functionality we still need, but they would be better suited as a data migration.

• Investigate our current set of management commands

[scottx611x]

Ref #2583

[jkmarx]

@scottx611x We discussed this during the dev meeting. Were there other commands which needed to be reviewed? #2583 removed the ones we agreed to.

[scottx611x]

I think there are still a few hanging around that we probably don't need:

core/management/commands/install_solr_synonym_plugin.py
core/management/commands/solr_synonyms.py
core/management/commands/uninstall_solr_synonym_plugin.py