Don't use an rpm for the web app in Tizen IVI extensions tutorial

Rather than use an rpm to install the web app (which requires a hard-coded user ID and is not recommended for Tizen packages), go back to manually installing the xpk file.

I also:

* Fixed a few formatting issues
* Straightened out some terminology
* Made it clear that the instructions are for Fedora Linux
* Made it clear that you can use VMware player OR workstation, but that these instructions use VMware workstation

Fixes BUG=https://crosswalk-project.org/jira/browse/XWALK-1363