Revert "BUG: DatetimeIndes.insert doesnt preserve name and tz"

This reverts commit e22c85626317bc74b33854558e05458f82686b51.
CI: move 3.4 build to mainstream / move 3.2 to experimental
API: Period should return NotImplemented as per the Python doc

if no comparison is implemented
Merge pull request #7379 from cpcloud/replace-no-match-7376

BUG: correct Period comparisons