[#59914] Add times for labor costs to the cost report and export

[as-op]

Ticket

https://community.openproject.org/work_packages/59914

What are you trying to accomplish?

Display the start and end times of a TimeEntry in the costs view and the excel export. (If activated by Setting.allow_tracking_start_and_end_times)

Screenshots

If the unit "Labor" is selected and no grouping is selected

In exported excel sheet "Labor"

What approach did you choose and why?

• Moved some code from PDF Timesheet to helper for reuse
• Split up table code to insert the column(s) after the spent_on column.
• In the excel sheet there are separate columns for each time.

Merge checklist

• Added/updated tests
• Tested major browsers (Chrome, Firefox, Edge, ...)