As promised add tests for generic enb that exercise enb instantiation with
multiple Radio Units and cells in all kind of combinations:

   FDD|TDD x LTE|NR x SDR|Lopcomm|Sunwave

and not only one particular case, but verifying instantiation with many
combinations at the same time - verifying how cells of different kinds are
handled and how radio units of different kinds are handled too. Using multiple
cells on top of several radio units of the same type is verified too.

For Lopcomm we also exercise generated cu_config.xml a bit.

See added tests for details.

Enb/generic tests are bootstrapped now.

From now one every fix to enb/generic and every semantic change will go on only
if it is accompanied test change or enhancement.