Deployment updates

Updates to deployment script and providing default .gitlab-ci.yml file (you have to run mv .gitlab-ci.yml.example .gitlab-ci.yml to start using it.

Default GitlabCI pipeline includes deployment for master and develop tags for production and stage hosts respectively.

You have to provide private ssh key in RUNNER_SSH_PRIVATE_KEY env variable (in CI/CD config in your gitlab panel, and RUNNER_KNOWN_HOSTS, which includes your ~/.ssh/known_hosts file contents.

It's better to generate separate ssh-key for deployments in order to prevent unnecessary access to your main ssh keyring.

Also removed usage of BaseObject::className() function prior to default ::class property