set reasonable bounds for PalletString everywhere

[brenzi]

PalletString should have a type argument defining the size of the bounded vec

pallets/primitives/src/common.rs

Line 32 in 8454f74

pub type PalletString = BoundedVec<u8, ConstU32<256>>;

256 by default is a lot because I suspect the chain DB blows it up to the bound (TBV)

Then we should allocate reasonable bounds everywhere. Especially these here should be reconsidered:

pallets/primitives/src/communities.rs

Line 329 in 8454f74

if self.name.len() > 20 {

pallets/primitives/src/communities.rs

Line 333 in 8454f74

if self.symbol.len() != 3 {