Issue:
If there is an issue with Foreman's Insights API,
insights-client --register command will fail with really long ugly HTML error.

Running `insights-client --test-connection` we can catch the error with
nice output like this:

Running Connection Tests...
=== Begin Upload URL Connection Test ===
Connection failed
=== End Upload URL Connection Test: FAILURE ===

=== Begin API URL Connection Test ===
Connection failed
=== End API URL Connection Test: FAILURE ===

Connectivity tests completed with some errors
See /var/log/insights-client/insights-client.log for more details.