generic TrustedGetter execution for sidechain pallets #1121
Description
Similar to how we want to generically execute trusted calls #1120, we also want to simplify any storage access without creating many getter variants manually. However, this is more involved if we want to a permissioned storage acess because the getters are not uniform, and the semantics of storage authorization does not exist within substrate. Hence, we can't derive an authorization scheme based on the metadata.
A further problem is that the storage access is not uniform. For double maps, for instance, is it the key1 or key2 that defines who can access the storage?
Hmm, this seems to be tedious, we will need some manual work always.