gh-92728: Restore re.template, but deprecate it (GH-93161)

Revert "bpo-47211: Remove function re.template() and flag re.TEMPLATE (GH-32300)"

This reverts commit b09184bf.
(cherry picked from commit 16a7e4a0)

Co-authored-by: Miro Hrončok <miro@hroncok.cz>