Save posts as draft

[ceolinwill]

Is your feature request related to a problem? Please describe.
Sometimes we start writing a post but it takes some time to finish them we risk losing everything if something happens.

Describe the solution you'd like
We should have a way of saving drafts of posts before we publish them. We should also have a new menu where we can list all drafts a user created.

Note
Drafts should be visible to the author only.