ENG-648: Update to pymongo 4.2

[daniilly]

Description

• Upgrading to pymongo 4.2 increases the minimum Python requirement to version 3.7.
• Added the dnspython package to handle connection URLs with SRV records.
• Updated dependencies to the minimum required versions and switched to forked packages for event-tracking and mongoproxy.
• Removed deprecated methods from the code.

Type of change

• Bug fix (fixes an issue)
• New feature (adds functionality)

Related issues

ENG-648

Checklists

Development

• Lint rules pass locally
• Application changes have been tested thoroughly
• Automated tests covering modified code pass

Security

• Security impact of change has been considered
• Code follows company security practices and guidelines

Code review

• Pull request has a descriptive title and context useful to a reviewer. Screenshots or screencasts are attached as necessary
• "Ready for review" label attached and reviewers assigned
• Changes have been reviewed by at least one other contributor
• Pull request linked to task tracker where applicable

[github-actions]

Checking git merge conflicts against https://github.com/openedx/edx-platform.git

Comparing with	open-release/nutmeg.master
Benchmark conflicts with main	304
Current conflicts	310
Summary	Adds 6 new conflicts. How can we do better?

New conflicting files with 'open-release/nutmeg.master'

common/djangoapps/pipeline_mako/templates/mako/js.html
common/lib/xmodule/xmodule/modulestore/perf_tests/test_asset_import_export.py
common/lib/xmodule/xmodule/mongo_utils.py
requirements/edx/paver.in

Comparing with	master
Benchmark conflicts with main	340
Current conflicts	348
Summary	Adds 8 new conflicts. How can we do better?

New conflicting files with 'master'

common/djangoapps/pipeline_mako/templates/mako/js.html
requirements/edx/paver.in
xmodule/modulestore/perf_tests/test_asset_import_export.py
xmodule/modulestore/split_mongo/mongo_connection.py
xmodule/mongo_utils.py