Introduce multi band amps

Introduce a new multi-band element that contains a list of Edfa element:
- reads multiple amps out of the element config.
- deduces frequency band from the amp in the list.

no autodesign yet: multi-band amps must have type_variety.

- checks that type variety of individual EDFAs is consistent with multiband
type variety
- demux and mux spectrum when propagate in multiband
- don't add a preamp or booster if a multiband amp is already defined.

The print of channel number is removed from equipment, since the channel number
may now depend on the path's amplifiers. This changes invocation results layout.

Signed-off-by: EstherLerouzic <esther.lerouzic@orange.com>
Change-Id: I44e77ff82e622cdee4021a7984d660317cb90cf9

gnpy/tools/cli_examples.py

@@ -228,7 +228,7 @@ def transmission_main_example(args=None):
             print(f'Input optical power reference in span = {ansi_escapes.cyan}{power_dbm:.2f} '
                   + f'dBm{ansi_escapes.reset}:')
         else:
-            print('\nPropagating in gain mode: power cannot be set manually')
+            print('\nPropagating in {ansi_escapes.cyan}gain mode{ansi_escapes.reset}: power cannot be set manually')
         if len(powers_dbm) == 1:
             for elem in path:
                 print(elem)