Decide how to manage "payments" when GNOT will be locked

[moul]

Currently, we have some contracts, such as r/demo/users, that are requesting payments for actions (https://gno.land/r/demo/users/users.gno).

However, we will lock GNOT tokens at launch (#2980), so we need to find an alternative.

Here are some options:

1. Use gas
2. Use another native std.Coin, but not GNOT
3. Use a grc20, which could be a future token
4. Disable these features until we enable token transfers

[thehowl]

I'm tempted to say 4: Disable these features until we enable token transfers. The reason is that I don't think we should officially have and support 'gnot' future tokens, because if they're used by the core team they're likely to have as much validity as unlocking gnot directly.

I am thinking that maybe we can support an alternative token, depending on the realm, to perform the "payment". This token can be awarded with a faucet depending on the project, or be airdropped similarly to GNOT to mimick the real token distribution. Then we can have a way to permanently switch it, in the realms, to using gnot instead; but use the "playground" token for the meantime.

[moul]

I'm also trying to avoid 3.

I'm considering a "reputation" GRC20 (or non-transferable) token that will have its own earning mechanism, such as contributions. We might not expect the token to serve as a payment method, but rather as a way to unlock features when you have "enough" reputation.