* test-runtime: GenesisBuilder runtime API impl + tests

This PR provides implementation of `GenesisBuilder` API for `substrate-test-runtime`, can be considered as reference imiplementation for other runtimes.
The `GenesisBuilder` implementation is gated by `gensis-config` feature.

Tested scenarios:
- default `GenesisConfig` to JSON blob,
- deserialization of `GenesisConfig` from custom JSON, and storing its keys into the Storage (genesis storage creation).
- creation of genesis storage using partial JSON definition,
- checking if invalid/renamed JSON files causes the runtime to panic,

* missing file added

* client: GenesisBuilder helper added

* feature renamed: genesis-config -> genesis-builder

* Update Cargo.toml

* Update Cargo.toml

* Update Cargo.toml

* Update Cargo.toml

* redundant function removed

* genesis builder helper: introduced RuntimeGenesisBuild

* test-runtime: get rid of unused T

* redundant bound removed

* helper: use GenesisBuild again

* tests adjusted for on_genesis

* test-runtime: support for BuildGenesisConfig

* helper: BuildGenesisConfig support

* Update client/genesis-builder/src/lib.rs

Co-authored-by: Davide Galassi <[email protected]>

* Update test-utils/runtime/src/test_json/readme.md

Co-authored-by: Davide Galassi <[email protected]>

* Update test-utils/runtime/src/test_json/readme.md

Co-authored-by: Davide Galassi <[email protected]>

* Update test-utils/runtime/src/genesismap.rs

Co-authored-by: Davide Galassi <[email protected]>

* jsons are now human-friendly

* fix

* improvements

* jsons fixed

* helper: no_defaults added

* test-runtime: no_defaults added

* test-runtime: patching fn removed

* helper: patching fn removed

* helper: moved to frame_support

* test-runtime: fixes

* Cargo.lock updated

* fmt + naming

* test-runtime: WasmExecutor used

* helper / test-runtime: struct removed

* test-runtime: merge fixes

* Cargo.lock + test-utils/runtime/Cargo.toml updated

* doc fixed

* client/rpc: test fixed (new rt api)

* client/rpc-spec-v2: test fix

* doc fix

* test-runtime: disable-genesis-builder feature

* fix

* fix

* ".git/.scripts/commands/fmt/fmt.sh"

* test-runtime: rerun added to build script

---------

Co-authored-by: Davide Galassi <[email protected]>
Co-authored-by: parity-processbot <>