topbar: Split out properties toolbar

Put properites toolbar code and UI definition into a seperate class and
template, respectively.

https://bugzilla.gnome.org/show_bug.cgi?id=726252
topbar: Split out collection toolbar

Put collection toolbar code and UI definition into a seperate class and
template, respectively.

https://bugzilla.gnome.org/show_bug.cgi?id=726252
topbar: Split out selection toolbar

Put selection toolbar code and UI definition into a seperate class and
template, respectively.

https://bugzilla.gnome.org/show_bug.cgi?id=726252
topbar: Split out wizard toolbar

Put wizard toolbar code and UI definition into a seperate class and
template, respectively.

https://bugzilla.gnome.org/show_bug.cgi?id=726252