Sort contacts by alpha order in Joplin

### As an author I want to be able to sort contacts by alpha order/ last edited so that I can find my contact more easily.

**Is your feature request related to a problem? Please describe.**
We have enough contacts now that it's a long list to scan without some sense of order.

**Describe the solution you'd like**
A similar sorting feature like we have for pages would be great!

**Describe alternatives you've considered**
Maybe a text box to search by name?

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

Start by locating the contacts list and the existing page-sorting behavior mentioned in the issue. Determine how alphabetical and last-edited ordering should be selected, then verify that contacts can be displayed using each requested order and remain easier to find than in the current unsorted list.

Written by the indexing model from the issue text.