Change frontend artefact deploy to run only for main branche

Related issues

Closes #85 (closed)

Acceptance criteria

• Implemented code changes don't diverge from the related issue.
• Documentation reflects the status quo after merge.
• Version number is incremented according to SemVer. (Snapshot versions are not merged/released.)
• Only released versions of dependencies are used (i.e. no snapshot versions).
• Pipeline still works.
• GitLab issue is up-to-date.

Proposed squash commit message

Change frontend artefact deploy to run only for main branche

• Change frontend artefact deploy ci pipelines job to run only if current branche = main branche
• Change are made only in Npm-Angular.gitlab-ci.yml template for ci pipeline.
• Frontend version increase to 1.2.1 (from 1.2.0)
• Update package-lock.json, to cover frontends version increase.
• Version update of backend, remove "-Snapshot" from version 1.1.0-Snapshot to cover rule: No Snapshot versions are merged.