Create status for Moment

[rafaels88]

A moment can be as draft or published.

API / WEB

• [ ] All draft moments does not appear in the API result.

Admin

• [ ] The moment form should have a drop-down which indicates the current state for the moment;
• [ ] The default status is Draft;
• [ ] It should have a new column in Moments list to show the current status
• [ ] It must be possible to change the moment status in the Event editing/creating page;
• [ ] It must be possible to change the moment status in the Person editing/creating page;