Make a new contact from the "choose contact" page

### As an author I want to be able to create a new contact from the choose contact page so that I don't have to open a new window for Joplin while I'm editing another page.

**Is your feature request related to a problem? Please describe.**
I'm always frustrated when I realize that the contact I need isn't created yet and then I need to open a new tab, sign into Joplin, and create a contact, then return to the original pane where I can close and reopen the contacts list.

**Describe the solution you'd like**
I'd like to be able to make a new contact from the selector just like when I create a new contact and then can create a new location from that page.

**Describe alternatives you've considered**
A clear and concise description of any alternative solutions or features you've considered.

**Additional context**
Add any other context or screenshots about the feature request here.