Added API Endpoints for account config

[dylanratcliffe]

This is where we will store config for the blast radius. This is the first step for https://github.com/overmindtech/api-server/issues/953

[DavidS-ovm]

This could be stored in ConfigService, which is already holding CLI configuration values. My thinking is that configuration schema is gonna be more prone to change and hardcoding it in sdp is not gonna suit us well.

[dylanratcliffe]

Decisions

• At the SDP level, we basically we leave it as-is, but pull the values to the top level
• At the database level, we use the existing logic as generic key value store, where the key identifies the schema of the thing we're saving, and the value is just the JSON of that thing. However since the current one is text, we should create a new table that stores all this stuff. This is a generic kv store where the values are always protobuf binary, like a protobuf document store.
  • For account-specific vs user-specific keys, we want to keep these in separate tables