Add Rococo chain-spec (#77)

* Add chain-spec for Rococo

* Execute `cargo run -- build-spec --raw > res/canvas-rococo.json`

* Update chain-spec

* Remove faucet

* Remove chain-spec fixture

* Make chain name clearer

* Add warning comment

* Update node/src/chain_spec.rs

Co-authored-by: Alexander Theißen <[email protected]>

* Update node/src/chain_spec.rs

Co-authored-by: Alexander Theißen <[email protected]>

* Revert "Update node/src/chain_spec.rs"

This reverts commit ca92285a

.

* Remove protocol id, consistency of chain id

* Distinguish local id

* Add protocol id back in

Co-authored-by: Alexander Theißen <[email protected]>