add a deposit to proposal

[5-mark]

User Story

As protocol I want to protect market participants from protocol abuse, e.g. bad actors proposing destructive activity for GameDAO or any other DAO running on the protocol.

To achieve this we require creators of a Proposal to deposit a sound amount of collateral to their proposal. This disincentivizes bad actors from abuse and creates more transparency for the voters.

Acceptance Criteria

1. add deposit to all Proposal extrinsics
2. lock deposited amount over lifetime of Proposal
3. return deposit after Proposal is either expired or voted on
4. if the user does not have enough GAME token to deposit, an error message is thrown ("insufficient funds")

Additional Information

• min deposit: 100 GAME

How to test

1. Create a proposal without deposit --> get error (e.g. "not enough mana").
2. Create a proposal for a future Blocktime --> see deposit reserved as collateral in wallet.
3. Create a proposal, check reserved amount and wait for expiry--> see amount unlocked and transferable again.