feat: adds allocations as streamable type

[corban-beaird]

Description

Adds allocations as a streamable type + some simplifications of the metric triggers.

Test Plan

• Run stream.py and make sure you receive proper updates regarding allocations

Commentary (optional)

Checklist

• [ ] Changes have been manually QA'd
• [ ] User-facing API changes need the "User-facing API Change" label.
• [ ] Release notes should be added as a separate file under docs/release-notes/. See Release Note for details.
• [ ] Licenses should be included for new code which was copied and/or modified from any external code.

Ticket

DET-9814