Rollup merge of #141237 - Qelxiros:139911-exact-div, r=workingjubilee

Implement ((un)checked_)exact_div methods for integers

tracking issue: #139911

I see that there might still be some bikeshedding to be done, so if people want changes to this implementation, I'm happy to make those. I did also see that there was a previous attempt at this PR (#116632), but I'm not sure why it got closed.

Author: workingjubilee