GUI Unit tests to confirm TCP port changes

[eostermueller]

snail4j uses at least half a dozen port numbers for various connectivity.
To insure snail4j can run on any machine, snail4j must be able to change configuration to use other port numbers without port conflicts.

This enhancement lays out the need for unit tests of the Angular UI that validate that TCP port numbers for a number of processes can be changed, and the SUT startup and load testing functionality still works.

Here are the port numbers that should be tested:
wiremock
h2
SUT JVM
glowroot
jmeter shutdown port.
snail4j agent -- which will be handled slightly different than the above.