0c902b6 backend: put numeric priority to sections per task type

Authored and Committed by praiskup 3 years ago
    backend: put numeric priority to sections per task type
    
    Assure that all the source builds are prioritized over the binary RPM
    builds, and that the normal builds are prioritized over the background
    builds.  Previously this fact was guaranteed only for a limited set of
    first jobs (+- 10), newly there are a sections of 1 000 000 items.
    
    Fixes: #1414