Only use types in pallets implementing MaxEncodedLen

[clangenb]

With a recent update, substrate changed the default requirements of a pallet's storage and dispatchable arguments. See paritytech/substrate#10652. This default shall become mandatory in the future for all pallets.

For most of our types, we can simply add a derive attribute MaxEncodedLen, which specifies the maximum number of bytes that an encoded value can have. To support this in all pallets, we need:

• Derive MaxEncodedLen for all types in:
  • typenum: derive parity-scale-codec an MaxEncodedLen for all types typenum#2
  • substrate-fixed: Derive MaxEncodedLen for all fixed types substrate-fixed#14
  • geohash: Make GeoHash length a const generic and derive MaxEncodedLen for it. geohash#2
• Convert all vecs to either WeakBoundedVec or BoundedVec and give them a sensible default for the size.
• Change PalletString type to a BoundedVec, which unfortunately means that we can't use the convenient String type in std.

For the time being, I added the pallet attribute #[pallet::without_storage_info] to pallets not yet supporting the MaxEncodedLen.

Pallets that still need migration:

• encointer-bazaar
• encointer-ceremonies
• encointer-communities