First PR to replace pytz with zoneinfo for UTC handling across codebase.
This PR migrates all UTC timezone handling from pytz to Python’s standard
library zoneinfo. The pytz library is now deprecated, and its documentation
recommends using zoneinfo for all new code. This update modernizes our
codebase, removes legacy pytz usage, and ensures compatibility with
current best practices for timezone management in Python 3.9+. No functional
changes to timezone logic - just a direct replacement for UTC handling.
https://github.com/openedx/edx-platform/issues/33980
This is an unused-as-of-yet utility function to generate a bunch
of ics files for a user's course schedule. Will be used as part
of the calendar_sync feature package.
AA-37
