Refactor account types

[strideynet]

Deals with the need for account types: Personal/Corporate and Savings/Current.

I'd like to propose we introduce proper controllable account types, with admins able to create new accounts.

The following could be controlled:

• Can account receive wages?
• What interest rate is paid on this account?
• What Transaction fee is charged on transactions made by this account?
• Can the account do investing/betting etc?
• I would ensure this is flexible so it is easy to add new feature flags for account types, i.e we can beta new features for certain account types

To implement server-side and front-end for this: 3 hours.