mo khan authored May 22, 2020 and Can Eldem committed May 22, 2020

* Move jobs to gitlab-ci.yml files that match the stage they belong to.
* Move linter job to build stage
* Add functional test jobs
* Reduce max size to 2 GB
* Pass the current pipeline image to the downstream jobs
* Replace `edge` tag with `latest`
* Use $CI_DEFAULT_BRANCH instead of master
* Move `.env*` files to config dir and update RELEASE instructions
* Combine `tag` and `release` stages into `deploy` stage as recommended in GitLab docs
* Make the `build-docker-image` job interruptible
* Fix issues found in code quality report