Enhancement: Don't spam logs when remote instance is down

[Ra72xx]

I use this integration to connect to a second server which is, however, only up on demand. This has the consequence that the logs of the "master" instance gets error entries every 10 seconds as soon as tthe "remote" instance is down and grows pretty huge.

While this is basically correct behaviour and can be adjusted with the "logger" integration, it might be more elegant to have an configuration option "don't complain if the remote instance is down" in the configuration or at least don't repeat the error every ten seconds.