Draft: Yocto CI Improvements (Release-Deployment, Workflow Adaptations, etc.)

This MR contains the following changes:

• Add job template for deployment to package repository
• Add release job template for creating GitLab releases
• Trigger release jobs on legacy tags and on main branch with semver tags

Attention: Some features might break existing CI configs in BSP projects. Also the following tests would still be helpful:

• Package Deployment: Testing for cross-platform and cross-version (Yocto) support as required/feasible
• Release Trigger Conditions: Testing of regex conditions for actual use case with new branching model

Here is an example for the content of the `.gitlab-ci.yml` of the `build-ktn-imx` repo using this

include:
  - project: 'sw/yocto/yocto-ktn'
    ref: feature/yocto-ci-improvements
    file:
      - '/ci/yocto-ktn-build.yml'

.variables-mx6: &variables-mx6
  variables:
    MACHINE: kontron-mx6ul
    BUILD_TARGETS: swupdate-img $BUILD_TARGETS_EXTRA

.variables-mx8: &variables-mx8
  variables:
    MACHINE: kontron-mx8mm
    BUILD_TARGETS: swupdate-img-qt $BUILD_TARGETS_EXTRA

build-mx6:
  extends: .build-machine
  <<: *variables-mx6

build-mx8:
  extends: .build-machine
  <<: *variables-mx8

build-release-mx6:
  extends: .build-machine-release
  <<: *variables-mx6

build-release-mx8:
  extends: .build-machine-release
  <<: *variables-mx8

deploy-release-package-mx6:
  extends: .deploy-release-package
  <<: *variables-mx6

deploy-release-package-mx8:
  extends: .deploy-release-package
  <<: *variables-mx8

create-release:
  extends: .create-release