Add a way to get the minimum balance via the algod REST API

[fabrice102]

Is your feature request related to a problem? Please describe.

Currently, TEAL smart contracts can compute the minimum balance of an account.
But otherwise, there is no simple way to compute it.

Describe the solution you'd like.

Add a field in the account struct returned by /v2/accounts/{address} that indicate the minimum balance.

Acceptance criteria

Requirement to update SDKs (could us code generator #1411 -- algod only)

[atrefonas]

This would be super helpful! thank you