add_location: TxDescriptor<{
    cid: {
        digest: FixedSizeBinary<4>;
        geohash: FixedSizeBinary<5>;
    };
    location: {
        lat: bigint;
        lon: bigint;
    };
}>

Add a new meetup location to the community with cid.

May only be called from T::TrustableForNonDestructiveAction.

Todo: Replace T::CommunityMaster with community governance: #137.