Use primitive-types crate to unify Substrate primitives

[sorpaas]

openethereum/parity-ethereum#9994

This uses the new primitive-types crate to allow common types in Parity Ethereum and Substrate to be shared.

• See Unify primitive types for Parity Ethereum and Substrate parity-common#86 for the PR on primitive-types.
• In ethereum-types, we define the conversion of uint types to hash. Because it assumes big endian, those are currently specific to Ethereum and if used out of context, it can lead to confusion. For example, parity-codec use little endian for U256 encoding. As a result, I created a new trait BigEndianHash that handles those conversions.
• ethereum-types-serialize crate is no longer used. So it's removed.

[niklasad1]

Not really introduced by this PR but the casting it to &[u8] is redundant because fixed_hash impl AsRef<[u8]>

See, https://github.com/paritytech/parity-common/blob/master/fixed-hash/src/hash.rs#L101-#L106

[niklasad1]

The code looks good to me but the code-organization with uint/hash still remains in this repo is hard to understand.

So now we have if I got it right:

• parity-common/fixed-hash
• parity-common/uint
• parity-common/primitives (both uint and hash)
• this repo (both uint and hash)

Can we move (uint, hash) in this repo to parity-common/primitives?

[sorpaas]

@niklasad1

this repo (both uint and hash)

I think we don't have uint and hash in this repo any more? (Or would you mind to send me a pointer where we still have it?)

[niklasad1]

@sorpaas I guess it matter of definition on what is but we still have two files named hash.rs & uint.rs which implement rlp macros and into/from conversions that's why I mean :P

[niklasad1]

@sorpaas what to do about this PR?

The end goal should probably be to deprecate this repo after paritytech/parity-common#97 right?

[dvdplm]

@sorpaas This can be closed yes?

[sorpaas]

Yes this can be closed. I think we moved most of the code to parity-common so may be we want to archive this repo.