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
    • osMacOSX
    • 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?)