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/docu/proxy_2.yuml

@@ -5,10 +5,10 @@
 [note: Example of instantiation for a GEN3 inverter!{bg:cornsilk}]
 [<<AbstractIterMeta>>||__iter__()]
 
-[InverterG3|addr;remote:StreamPtr;local:StreamPtr|create_remote();;close()]
-[InverterG3]++->[local:StreamPtr]
-[InverterG3]++->[remote:StreamPtr]
-
+[InverterBase|addr;remote:StreamPtr;local:StreamPtr|create_remote();;close()]
+[InverterBase]^[InverterG3]
+[InverterBase]++->[local:StreamPtr]
+[InverterBase]++->[remote:StreamPtr]
 [<<AsyncIfc>>||set_node_id();get_conn_no();;tx_add();tx_flush();tx_get();tx_peek();tx_log();tx_clear();tx_len();;fwd_add();fwd_log();rx_get();rx_peek();rx_log();rx_clear();rx_len();rx_set_cb();;prot_set_timeout_cb()]
 [AsyncIfcImpl|fwd_fifo:ByteFifo;tx_fifo:ByteFifo;rx_fifo:ByteFifo;conn_no:Count;node_id;timeout_cb]
 [AsyncStream|reader;writer;addr;r_addr;l_addr|;<async>loop;disc();close();healthy();;__async_read();__async_write();__async_forward()]