Enrich semantics of whitelist for different community types

[clangenb]

Considering that we will have several types of communities, we need to distinguish between them regarding their policy for the faucet. The below is taken from #340 (comment).

We may want to diversify further due to BeeDance and LoCoFlex. I guess that due to the different security assumptions we may even want:

WhitelistType::AnyCommunity
WhitelistType::AnyCommunityWithRules(Vec)
WhitelistType::Restricted(Vec)

assuming that CommunityIdentifier is the overarching type for communities of all rule types