update.sh parameter auto detection

[weickmanna]

When I used the update.sh, I had the project open in IntelliJ and directly updated it from there via the IntelliJ command line.

The update.sh asks for group id and artifact id. When we update an existing project, we can determine these parameters from the project itself. It would still be good to ask just in case. Also, the destination folder should rather be the current directory instead of "ktor-example".

For example:

Starting update in interactive mode ...
Enter path to your existing project [.]: 
Enter group-id of your existing project [<auto detected group id>]: 
Enter artifact-id of your existing project [<auto detected artifact id>]: 
Enter desired branch of ktorbase repo [master]: