[AGIPD][Dark] Add timings

Description

In this redmine ticket it was realized that AGIPD dark processing lacks timings for different cells. This MR addresses this issue by adding timings for the AGIPD dark notebook as well as the overall summary notebook.

How Has This Been Tested?

• TBD using unit tests.

Relevant Documents (optional)

agipd_timings.pdf

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

Reviewers

@tmichela @kluyvert