Previously, when a Tomcat connector failed to start it was assumed that
the failure was due to the port being in use and a PortInUseException
was thrown. Unfortunately, this assumption doesn’t always hold true.
For example, a Tomcat connector will also fail to start when its using
SSL and the key store password is wrong. This could lead to incorrect
guidance from the PortInUseFailureAnalyzer indicating that a port clash
had occurred when, in fact, it was the SSL configuration that needed to
be corrected.

Unfortunately, Tomcat only tells us that the connector failed to start.
It doesn’t provide access to the exception that would allow us to
determine why it failed to start. This commit updates the embedded
Tomcat container to throw a ConnectorStartFailedException in the event
of a connector failing to start. A new failure analyser,
ConnectorStartFailureAnalyzer, has been introduced to analyse the new
exception and offer some more general guidance.

Closes gh-6896