[Task]: Implement Timers

[damccorm]

What needs to happen?

Part of #20510 - designed here - https://docs.google.com/document/d/1rcKa1Z6orDDFr1l8t6NA1eLl6zanQbYAEiAqk39NQUU/edit?usp=sharing

Issue Priority

Priority: 2

Issue Component

Component: sdk-go

[damccorm]

@riteshghorse I split state and timers into 2 issues to make public tracking a little easier (I'm planning on adding a bunch of subissues for State as well). Could you self-assign this one by commenting .take-issue? GHA is currently quite backed up, so the actual assignment could take a while.

[riteshghorse]

SGTM, thanks

[riteshghorse]

.take-issue