Linter will check packages submitted for CI build. If error was found,
build will not be allowed.
To ensure that all build.sh scripts are consistent and have at least
minimal allowed quality, linter is permanently enabled for all branches
and pull requests.
* Move package building implementation from config to a separate script.
* Implement new tag '%ci:no-build' to allow immediately stop build with status 'passed'.
Leonid Plyushch