feat: uAgent almanac registrations

[bryanchriswhite]

Changes

• adds AlmanacRecord and AlmanacRegistration entities
• adds misc. absent type annotations
• refactor test contract download helper
• add uagents repo (private at time of writing) as a git submodule dependency (for e2e tests)

---

Code Review Checklist (to be filled out by reviewer)

• Description accurately reflects what changes are being made.
• Either the PR references an issue (via the "Development" combobox) or the description explains the need for the changes.
• The PR appropriately sized. (:see_no_evil: :sweat_smile:)
• New code has enough tests.
• New code has enough documentation to answer "how do I use it?" and "what does it do?".
• Existing documentation is up-to-date, if impacted.

[Jonathansumner]

Amazing work, bud!