Generate a queueing model to run checks programmed and manually triggered.

The queue must consider:

• A prioritization due to manual invocation (via Flask app)
• A programmed checking (once a month, twice a semester, etc.)
• An automatic programming due config changed (i.e., 1 hour after changed detected)

The queue may be a file or SQLite database to be simpler than a MySQL instance and more efficient to query than a plain text file.