Add timestamps to package task display (fixes #832)

[mcantelon]

Added display of package task start and completion date/time when displaying package activity tasks in the dashboard.

Fixed warnings during date conversion to ISO 8601 format.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 48.88%. Comparing base (3102539) to head (c82080e). Report is 2 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #937 +/- ## ======================================= Coverage 48.88% 48.88% ======================================= Files 103 103 Lines 5533 5533 ======================================= Hits 2705 2705 Misses 2597 2597 Partials 231 231 ```

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[sevein]

Hi Mike! I haven't tested it yet, but I'm curious to know if it fits well on all screen sizes. How does it look? In Legacy Enduro, some columns were hidden depending on the window size.

[mcantelon]

@sevein Hi Jesus! Here's what it looks like in a narrow window (it doesn't seem to hide columns):

[mcantelon]

Thanks @sevein !