Implement basic storage of lister information

This adds a pair a functions to the backend:

• get_or_create_lister pulls the record for a given lister from the database
• update_lister updates the record for a given lister in the database

This is one of the basic building blocks for the integration of lister information directly in the scheduler database.

Related to #2442 (closed).

Test Plan

new tox tests for both new functions

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Migrated from D3271 (view on Phabricator)