remove `flux-perilog-run`

[grondo]

This PR simply removes the deprecated flux-perilog-run script along with tests that used it.

The only other thing that could be added here is to throw an error if flux perilog-run is used in a prolog or epilog config. However, since we know all the machines that are likely using prolog/epilog and they've all transitioned to using the per-rank config, this doesn''t seem necessary. Admins will also notice quite quickly when the prolog and/or epilog fails.

(However, it is trivial to add if others think it would be helpful)

[grondo]

Thanks! I've set MWP.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 83.61%. Comparing base (ae1f516) to head (a3f94b6). Report is 3 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #6447 +/- ## ========================================== - Coverage 83.64% 83.61% -0.04% ========================================== Files 524 523 -1 Lines 87693 87488 -205 ========================================== - Hits 73355 73153 -202 + Misses 14338 14335 -3 ``` [see 12 files with indirect coverage changes](https://app.codecov.io/gh/flux-framework/flux-core/pull/6447/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flux-framework)

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