Create views for the models

[ewjoachim]

Create basic ModelForms and Views for Detail, Creation, List, Update (and Deletion when applicable ?) for :

• Songs
• Parts
• Singers
• Sections

Some highly specialized views like Auto-Song Creation from Dropbox exploration or assignement of singers to their parts in songs will be done in their own ticket. This is for the simple views.

Idea : use Selectize to improve display of ChoiceFields.