Support checks from multiple regions

## Done Criteria
Our core checks (data storage, retrieval) are:
1. Run from multiple regions
2. Have their metrics attributed with the "testing-from" region in our metric datastore
3. Any UI of our metrics make clear where the check was run from

## Why Important
Dealbot gives a truer sample of performance from wherever it is running. It's currently running from the EU, which biases its results for EU-based users.

## Open questions
1. What geographic identifier(s) will we use when attributing the "testing-from" region?
- [Hetzner location names](https://docs.hetzner.com/cloud/general/locations/) (e.g., fsn1, sin)?
- [IATA airport codes](https://en.wikipedia.org/wiki/IATA_airport_code) (e.g., LAX, LHR)?
- [AWS regions](https://aws.amazon.com/about-aws/global-infrastructure/regions_az/) (e.g., us-east1)
- [ISO 3166 country codes ](https://en.wikipedia.org/wiki/List_of_ISO_3166_country_codes) (USA, CAN)
2. Do all SPs get tested by all dealbot instances or do they get divided up amongst the dealbot instances?

## Notes
1. This is a placeholder for now. Given it's not a GA priority, it hasn't been scoped out more.
2. I assume we'll still have one global database instance that all dealbot instances use