Team creation form

The team creation form is in place. A couple of fixes are due:

• It would be good that we describe, somewhere, what the different privacy levels mean.
• It would be better to have the whole form completable at once, in a single page, instead of creating the team and then editing its attributes
• It would be good if, by clicking on the team (at the user micro-site), the system took the user to the team edition page as for other objects. Some harmonization should be put in place for this.