gh-35540: For groups: generic centralizer, subgroup methods; improving center
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### :books: Description
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Only certain groups (mainly permutation groups) implement
`centralizer()` and `subgroups()` methods, but GAP provides this
functionality for more general groups. We provide this implementation
for all finite groups implemented via GAP, which seems to do a brute-
force approach. Likewise, the `center()` method for infinite groups
seems to run forever, and we protect against that. We add an explicit
`center()` method for Heisenberg matrix groups (which have a GAP group)
both to demonstrate that specific (infinite) groups can implement it and
to provide this information.
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### :hourglass: Dependencies
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URL: https://github.com/sagemath/sage/pull/35540
Reported by: Travis Scrimshaw
Reviewer(s): Daniel Bump
