CI: Release start (#788)

* Initial version

* Fix branch pattern

* Fix template

* Update .github/ISSUE_TEMPLATE/release.md

Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

* Update .github/ISSUE_TEMPLATE/release.md

Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

* Rebase master and fmt

* Swap out Polkadot JS section for integration tests + remove tags

* remove tags

Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>