fix/submitter performance

[ziggy-cyb]

Description

The submitter would run into problems if there were multiple submissions being processed at once, running into issues with duplicating submissions, or hitting memory limits and crashing. This PR should fix these issues by better pacing submission processing.

• Changed poll plugin to be a recursive function. This blocks new submissions from processing while a submission is being processed, but still allows polling on a timed basis
• Changed queue service to only grab one submission at a time. This stops from too many webhook requests to run at the same time

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce
the testing if necessary.

• Manual testing with a local endpoint and db instance

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation and versioning
• I have updated the architecture diagrams as per Contribute.md OR added an architectural decision record entry