Rewrite the way of accessing accounts

[MrIvanPlays]

Closes #167

[lokka30]

I'm thinking we eliminate createIfNotExists entirely and economy providers will implement that logic by standard.

[MrIvanPlays]

I'm thinking we eliminate createIfNotExists entirely and economy providers will implement that logic by standard.

what if i don't want to create an account if it doesn't exist?

[lokka30]

I'm thinking we eliminate createIfNotExists entirely and economy providers will implement that logic by standard.

what if i don't want to create an account if it doesn't exist?

I don't see the use case. There's hasAccount to check if one exists, and if someone wants to retrieve it, they will use retrieve and it will – assuming no errors – return an account, new or existing, that only matters to the economy provider.