Sorting by Duration Field in Attendance Model

[aswinshenoy]

Is your feature request related to a problem? Please describe.
The list of entries in the attendance model are not sortable by duration, neither are they filterable

Describe the solution you'd like
The duration field in the attendance model needs to be sortable like others.

Describe alternatives you've considered
Presently there is no way in the admin to sort attendance entries by duration.

Additional context
Currently, the list looks like this and doesn't have a sort filter for duration field in attendance model

[aswinshenoy]

This issue arises because duration field is a calculated field from session_start and session_end and not actually a model field.

[abhishekbvs]

What all filters are needed for the duration field? Can u give the constraints according to the requirement?