Pass buildrequired modules built against all compatible base module streams to MMDResolver.
    
    Imagine we have "platform:f29.0.0" and "platform:f29.1.0" base modules.
    We also have "DBI" module we want to build agaisnt "platform:f29.1.0".
    This "DBI" module depends on "perl" module which is only build against
    "platform:f29.0.0".
    
    Currently, DBI build would fail to resolve the dependencies, because
    it wouldn't find "perl" module, because it is built against different
    platform stream.
    
    This PR changes the MSE code to include buildrequired module builds built
    against all the compatible platform streams.
    
    It does so by introducing following changes:
    
    - MSE code uses new get_base_module_mmds() method to find out all the
      compatible platform modules. This needed new methods in DBResolver
      and MBSResolver.
    - For each buildrequired module defined by name:stream, the MSE code then
      finds particular NSVC built against each compatible platform module.
    
    Side effect of these code changes is that every module now must buildrequire
    some base module.