Generate koji tag from MBS and use informative name
    
    koji now supports tags with max length of 256, we can use
    more informative tag name instead of the hash one.
    
    The new format of koji tag name is:
    
        module-<name>-<stream>-<version>-<context>
    
    However when the generated tag's length > (256 - len('build')), we
    fallback to the old way of name in hash format (module-<hash>).
    
    In this change, koji tag is always generated from MBS itself, even
    with pdc resolver.
    
    FIXES: #918 #925