Private Voting

[jpaulet]

Add the "Private voting" option in the create process:

Clicking the option, should open a popup, with the same text and a input to add the password.

Once the process is created, it should be stored as a "private" and set the password.

After implementing it in the creation flow, make sure that the voting page is also finished:

• [ ] Add "Private voting" into the creation flow
• [ ] Make sure everything is stored correctly
• [ ] Add the new feature in the voting process: https://github.com/vocdoni/ui-components/issues/165
• [ ] Test it