* The storage runtime interface should not enforce a hash type

Currently the runtime interface enforces `H256` as hash type, but in the
future people could use whatever they want as hash type. The hash type
always needs to match between the runtime and the node, but that is
already required.

* Update primitives/externalities/src/lib.rs

Co-Authored-By: thiolliere <[email protected]>

* Add sha2-256 hash function

Widely used hash function, supported by bitcoin and ethereum

* Add runtime io support

* add test

* add test

* Update hashing.rs

* Update hashing.rs

* Pass Extensions instead of individual objects.

* Move TransactionPool to a separate ExternalitiesExtension.

* Fix compilation.?

* Clean up.

* Refactor testing utilities.

* Add docs, fix tests.

* Fix doctest.

* Fix formatting and add some logs.

* Add some docs.

* Remove unused files.

* Adding first rough ouline of the repository structure

* Remove old CI stuff

* add title

* formatting fixes

* move node-exits job's script to scripts dir

* Move docs into subdir

* move to bin

* move maintainence scripts, configs and helpers into its own dir

* add .local to ignore

* move core->client

* start up 'test' area

* move test client

* move test runtime

* make test move compile

* Add dependencies rule enforcement.

* Fix indexing.

* Update docs to reflect latest changes

* Moving /srml->/paint

* update docs

* move client/sr-* -> primitives/

* clean old readme

* remove old broken code in rhd

* update lock

* Step 1.

* starting to untangle client

* Fix after merge.

* start splitting out client interfaces

* move children and blockchain interfaces

* Move trie and state-machine to primitives.

* Fix WASM builds.

* fixing broken imports

* more interface moves

* move backend and light to interfaces

* move CallExecutor

* move cli off client

* moving around more interfaces

* re-add consensus crates into the mix

* fix subkey path

* relieve client from executor

* starting to pull out client from grandpa

* move is_decendent_of out of client

* grandpa still depends on client directly

* lemme tests pass

* rename srml->paint

* Make it compile.

* rename interfaces->client-api

* Move keyring to primitives.

* fixup libp2p dep

* fix broken use

* allow dependency enforcement to fail

* move fork-tree

* Moving wasm-builder

* make env

* move build-script-utils

* fixup broken crate depdencies and names

* fix imports for authority discovery

* fix typo

* update cargo.lock

* fixing imports

* Fix paths and add missing crates

* re-add missing crates