TS: Print help banner on `mvn install` without params.

Jaikiran:

{qoute}
Would it be possible to somehow print out all the available options and
params that need to used, when you run mvn clean install from the
testsuite modules? Something like a help?{qoute}

Not sure if it will be possible to check the condition "There are no params", but we can print it every time as well.