Remove pallet::without_storage_info from bridge GRANDPA pallet

[svyatonik]

related to #1433
it'll stay draft until the similar issue with system pallet is resolved (see explanation below)

I've tried to implement that, but looks like there are some more general problems that need to be solved first. Right now the main issue is that the generic header is not implementing the MaxEncodedLen. And it is what we're storing in the runtime storage. The similar case is with the system pallet, which is storing recent headers - so let's see how frame guys will solve it there. I assume that we'll have some upper bound on header size? Then we'll also need to do similar thing here. I've been wrong obviously - system pallet is only storing block hashes. But there's still problem with paras pallet (https://github.com/paritytech/polkadot/blob/master/runtime/parachains/src/paras/mod.rs), which doesn't generate storage info too.

With parachains finality pallet it is even more complex. because we deal with multiple parachains there. So we shall use max(max-of-parachain-1, max-of-parachain-2, ...).

The fix for messages pallet looks easier - we already are limiting the message size. The only thing is that it is missing from the pallet configuration (it is configured through the message verifier trait).

UPD: I doubt that the parachains pallet will be fixed, because it is deployed at relay chain

[bkontur]

lgtm