S allius/issue334 (#335)

* move forward_at_cmd_resp into InfosG3P class

- the variable is shared between the two connections
of an inverter. One is for the TSUN cloud and the
other for the device.

* use inverter class to share values between
the two protocol instances of a proxy
- move forward_at_cmd_resp into class InverterG3P
- store inverter ptr in Solarman_V5 instances
- add inverter ptr to all constructurs of protocols
- adapt doku and unit tests-
- add integration tests for AT+ commands which
  check the forwarding from and to the TSUN cloud

* adapt and improve the unit tests
- fix node_id declaration, which always has a / at
  the end. See config grammar for this rule
- set global var test to default after test run

app/src/inverter_base.py

@@ -41,7 +41,7 @@ class InverterBase(InverterIfc, Proxy):
                                 self.remote)
 
         self.local = StreamPtr(
-            prot_class(self.addr, ifc, True, client_mode), ifc
+            prot_class(self, self.addr, ifc, True, client_mode), ifc
         )
 
     def __enter__(self):
@@ -122,11 +122,11 @@ class InverterBase(InverterIfc, Proxy):
             self.remote.ifc = ifc
             if hasattr(stream, 'id_str'):
                 self.remote.stream = self.prot_class(
-                    addr, ifc, server_side=False,
+                    self, addr, ifc, server_side=False,
                     client_mode=False, id_str=stream.id_str)
             else:
                 self.remote.stream = self.prot_class(
-                    addr, ifc, server_side=False,
+                    self, addr, ifc, server_side=False,
                     client_mode=False)
 
             logging.info(f'[{self.remote.stream.node_id}:'