Payments. Provider stores Consumer promises (state)

[Waldz]

No description provided.

[Waldz]

In order to get paid later for provided services
As a Node operator
I want to store received promises that later I could clear them

Acceptance Criteria:

• Store received promises locally

• Check promise validity and provide error if promise doesn’t match:

1. Consumer’s signature
2. Proposal's conditions
3. Consumer’s balance is lower then promised amount (check on blockchain)