Provide an option to sort the mails

[fnumrich]

Problem

Currently there's no option so change the sort order of the mails.

Proposal

Provide the option to define the order of the mails like:

• by date ascendending
• by date descendending

Nice to have:

• by title ascending/descending
• by sender ascending/descending

Prior Art (Optional)

Implemented in most of the popular mail readers like Thunderbird.