Fix #11083: add Ben back to codeowners, remove Sean temporarily, clean up TODOs (#11221)
Fix #11083: add Ben back to codeowners, remove Sean temporarily, clean up TODOs (#11221)

* Revert "Update CODEOWNERS (#11084)"

This reverts commit 7f999d038a413a6fde633b14bdd7f607114cdcca.

* Make CODEOWNER changes.

* Address review comments.

* Update codeownership of release-process pages.
oppia/oppia,oppia/oppia,brianrodri/oppia,kevinlee12/oppia,oppia/oppia,kevinlee12/oppia,brianrodri/oppia,kevinlee12/oppia,kevinlee12/oppia,brianrodri/oppia,brianrodri/oppia,oppia/oppia,kevinlee12/oppia,brianrodri/oppia,oppia/oppia