Externalize the fragment FormPage

Create a new class FormPageFragment extending Fragment. This one is
dedicated to be the generic fragment of all form pages. 

https://github.com/TAurelien/SimuImmo/issues/issue/19

Signed-off-by: TAurelien <aurelien.ticot@gmail.com>
Merge branch 'feature_FragmentInstance' into feature_SwipeView