Parachain improvements (#1905)

* Parachain improvements

- Set the parachains configuration in Rococo genesis
- Don't stop the overseer when a subsystem job is stopped
- Several small code changes

* Remove unused functionality

* Return error from the runtime instead of printing it

* Apply suggestions from code review

Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>

* Update primitives/src/v1.rs

Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>

* Update primitives/src/v1.rs

Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>

* Fix test

* Revert "Update primitives/src/v1.rs"

This reverts commit 11fce278.

* Revert "Update primitives/src/v1.rs"

This reverts commit d6439fed.

* Revert "Return error from the runtime instead of printing it"

This reverts commit cb4b5c08.

* Revert "Fix test"

This reverts commit 0c5fa1b5.

* Update runtime/parachains/src/runtime_api_impl/v1.rs

Co-authored-by: Sergei Shulepov <sergei@parity.io>

Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
Co-authored-by: Sergei Shulepov <sergei@parity.io>
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