PerunMinDeposit prevents (one-sided) zero funding

[leandro-ro]

Location:

perun-polkadot-node/node/runtime/src/lib.rs

Line 274 in 95ba0c9

pub const PerunMinDeposit: Balance = 10;

Problem:

Due to PerunMinDeposit set to 10 (Plancks), it is impossible to, e.g., open a payment channel with one participants funding being zero.

Proposal:

Set PerunMinDeposit to 0.

[matthiasgeihs]

https://github.com/perun-network/perun-polkadot-pallet/blob/39a6176cb4a78aac329bddd6d9dc8b307b03fea7/src/lib.rs#L226

This is the place where it fails.

But I think the real problem is that the funder should never call deposit if the balance is 0.

https://github.com/perun-network/perun-polkadot-backend/blob/1cf5c72ae46f387cacdf7083ca38da44db8ddfab/channel/pallet/funder.go#L56