save: investigate use of base64 encoded urls in headless browser

[machow]

In PR #499 we replaced saving to a temporary file with inputting base64 encoded rendered html into a headless browser.

Browser url limits are a bit tricky, but they do exist. Let's investigate potential issues we might hit by passing long urls to the headless browser.

Alternatively, it might save us time to revert back to saving a temporary file, since the gt R package has used that approach for ~6 years with little issue.

I would vote for reverting, just to align with gt R. It's likely modern browsers have large url limits, but it's tricky to verify.

[jrycw]

@machow , I wasn’t aware of this issue. Please feel free to revert to the temporary file approach if needed.