Macro for constructing a high-level type-safe wrapper around substrate storage about substrate

[gavofyork]

crate substrate_storage would define all storage values used in substrate.

what is this fascination with collecting common lexicographical items into crates!?

while i agree with the general gist of this issue, storage elements should be declared (and exported as needed) in the modules that use them, not in some monolithic collection, just like constants, types, helper functions and tests.

[rphmeier]

@gavofyork sure, then those particular keys like :auth: and :code: should be defined in runtime-std as there isn't really anywhere else suitable.

[rphmeier]

In general the goal of extracting the constants out to a separate crate is to allow type-safe access of the storage without having to link to the entire runtime.