Use RDS for build size tracking (#64303)

Use RDS for build size tracking (#64303)

Summary:
This adds 2 utilities: `register_rds_table` and `rds_write`. `register_rds_table` needs to be called once with the schema for the data that `rds_write` will write. These go to a lambda called `rds-proxy`, which will write to/read from the DB as necessary. This data can then be arbitrarily queried via `rds-proxy` (for use in CI) or on metrics.pytorch.org (for analysis).

It also hooks these up for build size tracking (which previously was not working on GHA)

TODO:
* verify output in logs + clean up prints

Pull Request resolved: https://github.com/pytorch/pytorch/pull/64303

Reviewed By: malfet, seemethere

Differential Revision: D30711934

Pulled By: driazati

fbshipit-source-id: 0af808ddf528a24875a378caeb1aa9cb0693f802