Provide better error if passing a bad arg to install.sh

[mwrock]

I accidentally mistyped --install-postgresl and got an error that was not obvious:

ERROR: Invalid argument provided
Use -h or --help to view the available options.

Now one might think that ^^^ is obvious enough. What made it confusing is that the script did a bunch of stuff first (like installing hab) so it made me woder if that error was coming from inside the script and not my own command.

Ideally we would catch the error first thing or we would actually print out the --help with the error.