Add CLI commands

[jkemp101]

Some initial work was explored in #48 to allow inspecting/dumping queues from the command line. Administrators could benefit from a CLI that allowed manipulating queues and tasks.

[tinvaan]

@jkemp101 is there a feature spec or a rough list of commands available for this?

#48 had the following, but the branch was deleted. are you able to restore it?

• Print queue statistics
• Dump all tasks to /tmp/tasks.db file and clear queue:
• Dump all tasks in queue and do not save them to sqlite3 database
• Dump a batch of tasks to /tmp/tasks.db but leave them on queue
• Count number of tasks dumped to sqlite3 database
• View dump info in db file

[jkemp101]

We haven't really had a big need for this and therefore haven't given too much thought about moving forward with adding a CLI. Is this something you have a need for?

[tinvaan]

Honestly I'm not going to use it as much either, but I'm happy to help with triaging/fixing if needed. However, if there isn't a real need for anyone, probably best to close this issue for now.