Sudo script support

Adds sudo command support for inline scripts, script files, and script URLs for issue #343

* adds `scriptInterpreter` field to script steps, and `interpreterArgsQuoted` boolean to quote all arguments to the interpreter.
* Updates use of CLI argument strings passed to the execution service layer: adds ExecArgList class to encapsulate list of arguments and their quoting requirements

TODO:

- [ ] update documentation
- [ ] update/test XML/YAML Job serializing
- [ ] GUI description of "args quoted" flag