Running each strategy on a different sub-account

[CharlesFr]

Add the ability to pass sub-account names from the strategy in order to trade them on separate sub-accounts.

This is primarily to make PnL calculations more manageable. Also provides isolation between strategies for better risk mitigation.

[atkinson]

Nice - This means that Strategy will need the following:

a) The name of the sub-account.
b) The env-var from which to load the API key.

The env-vars should be namespaced, e.g. FTX_KEY_SUBACCOUNT
As we currently have only one strategy, this can be done now or later.

[CharlesFr]

Would it be a bad idea to have API keys managed directly in the admin panel?