Make a cleanup in project labels

Do a cleanup in project labels used for issues and merge requests:

• Prepare a list of labels that should be used (with executor::, os::, platform:: prefixed labels)
  • organization labels:
    • high priority
    • ~pick-into-stable
    • ~"waiting for feedback"
    • wontfix
    • release
  • request type labels:
    • ~bug
    • customer
    • direction
    • documentation
    • ~"feature proposal"
    • ~improvement
    • ~performance
    • regression
    • security
    • ~support
    • ~"technical debt"
  • features:
    • ~artifacts
    • cache
    • executors
  • executors:
    • executordocker
    • executordocker-machine
    • executorkubernetes
    • executorparallels
    • executorshell
    • executorssh
    • executorvirtualbox
  • os:
    • ~"os:FreeBSD"
    • osLinux
    • ~"os::MacOSX"
    • osWindows
  • platforms:
    • platformarm
    • platformi386
    • platformx86_64
• Ensure that all labels have a description
• Select prioritized labels (if any)
• Look on issues/MRs with labels planned for remove - replace them with new (if any) - [x] ~internal
• Remove deprecated labels (should we remove old labels?)