[welcome page] use item delegate to add html style to labels

[nirvn]

@m-kuhn , @nyalldawson , @NathanW2 , please excuse the pitiful state of this branch. It's not meant to be committed, but simply to brainstorm about the possibility of adding html styling to the welcome page's recent project list.

Using this branch, the home page looks like this:

There's lots of unfinished stuff in there (e.g., different text color for disabled items, translatable "untitled" if we decide to label untitled projects as such, etc.). But as a general question, is it worth investing energy in improving and cleaning up?

[m-kuhn]

I think it's worth polishing the welcome page.
Originally I wanted to make it a QML widget but then I postponed that to when Qt 5 will be standard and newer QtQuick stuff is included.
Now I am also playing with the idea to make it an entire html/js page which would allow to include some nice effects (e.g. clicking on the icon expands it vertically to show more information, bigger picture with a short animation...)