Option to sort by last name in Contacts

[doktorszike]

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Checklist

• [x] I am using the latest version - 1.4.3
• [x] I checked, but didn't find any duplicates (open OR closed) of this issue in the repo.
• [x] This issue contains only one feature request. I will open one issue for every feature I want to request.

Describe the feature you want

Right now, Koler automatically sorts by first name. I would like to have the option to switch to sorting by last name.

Is your feature request related to a problem? Please describe it

There is no option to change to sorting by last name.

Additional context

How will you/everyone benefit from this feature?

Better sortability and more relevant order of contacts. Also, the option itself so Koler can better fit to your usecase.