feat: refine AutoCert logic

[eternal-flame-AD]

It seems like the Autocert logic can be quite confusing and errors can be implicit ..

This tries to:

• make errors more explicit and noisy
• corrected a missing ALPN issue for the TLS challenge part, which should make success rate higher as long as one of TLS/HTTP challenge passes.
• allows the staging endpoint to be used for initial setup which should reduce friction or unexplained failures from ratelimiting

[codecov]

Codecov Report

❌ Patch coverage is 0% with 28 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.77%. Comparing base (9e1455f) to head (e4a7205).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
runner/runner.go	0.00%	28 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #843      +/-   ##
==========================================
- Coverage   79.54%   78.77%   -0.78%     
==========================================
  Files          56       56              
  Lines        2645     2671      +26     
==========================================
  Hits         2104     2104              
- Misses        450      476      +26     
  Partials       91       91              

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[eternal-flame-AD]

Holding this for a moment pending if I can find the reason for #836, just so that we don't need to fix/add some other check later

[jmattheis]

Should these changes be released right now?

[eternal-flame-AD]

I am not sure is this a regression (doesn't seem like it, but that could be just because this renewal code path is so cold regression don't show up quickly)? If so then probably. Otherwise up to you I am neutral

I currently don't have a machine/IP I can test this process end to end, so far my testing only goes the challenge process works and errors work and ALPN happened not that it solved any particular issues, if you have one can you test it?