Document how to customize and host r4ss's html output

[k-doering-NOAA]

This resolves #544 and resolves #564.

This is still a draft, because it starts a vignette, but I'm not sure if it is headed in the right direction or not. Feedback on the details added to the documentation would be helpful, also.

I'm adding this as a draft PR to keep it more visible.

[codecov]

Codecov Report

Merging #694 (d4df610) into main (c06efba) will decrease coverage by 0.06%.
The diff coverage is 29.59%.

❗ Current head d4df610 differs from pull request most recent head 05ffe94. Consider uploading reports for the commit 05ffe94 to get more accurate results

@@            Coverage Diff             @@
##             main     #694      +/-   ##
==========================================
- Coverage   55.78%   55.71%   -0.07%     
==========================================
  Files         111      111              
  Lines       25920    25963      +43     
==========================================
+ Hits        14459    14466       +7     
- Misses      11461    11497      +36     

Impacted Files	Coverage Δ
R/NegLogInt_Fn.R	0.00% <0.00%> (ø)
R/PinerPlot.R	0.00% <ø> (ø)
R/RebuildPlot.R	0.00% <ø> (ø)
R/SSMethod.Cond.TA1.8.R	0.00% <ø> (ø)
R/SSMethod.TA1.8.R	77.84% <ø> (ø)
R/SS_ForeCatch.R	0.00% <ø> (ø)
R/SS_Sensi_plot.R	96.16% <ø> (ø)
R/SS_changepars.R	81.20% <ø> (ø)
R/SS_fitbiasramp.R	69.86% <ø> (ø)
R/SS_html.R	84.25% <ø> (ø)
... and 76 more

---

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[k-doering-NOAA]

I won't have time to finish this up, so @iantaylor-NOAA will take it over at some point in the future! Leaving this open as a draft PR just to keep it visible.