Use SSH forwarding to connect remotely to dbus instance where `bluechi` service is connected

[mwperina]

Using python-bluechi module within integration tests has been introduced as a part of #485 . But clients using python-bluechi need to be executed on the same machine, that bluechi controller is runnig.

Here is our current intergration tests setup:

 __________________________________________________________________________________________________
|                                                                                                  |
|    Testing host                                                                                  |
|                                                                                                  |
|                         -----------------------------------------------                          |
|                        |                                               |                         |
|                        |  Execution process of integration tests code  |                         |
|                        |                                               |                         |
|                         -----------------------------------------------                          |
|                                                                                                  |
|                                                                                                  |
|                                                                                                  |
|     --------------------------------      ----------------------      ----------------------     |
|    |                                |    |                      |    |                      |    |
|    |  bluechi controller container  |    |  node foo container  |    |  node bar container  |    |
|    |                                |    |                      |    |                      |    |
|     --------------------------------      ----------------------      ----------------------     |
|                                                                                                  |
 --------------------------------------------------------------------------------------------------

So to use python-bluechi in integration tests we need to copy this module source file into bluechi controller container, because it needs to connect to the same system dbus instance where bluechi controller container. This approach makes the usage of python-bluechi in integrations tests harder and if you need to check the output of the client, then it's even more problematic.

So it would be great if we could use SSH tunnel between testing host and dbus instance running within bluechi controller container so python-bluechi clients could be easily integrated into the test code.

https://nikhilism.com/post/2023/remote-dbus-notifications/