Updated console logging

[rviscomi]

This is a followup to #115, which introduced logging diagnostic info. These changes include:

• Using console groups for each metric log
  • Moving all instances of the extension prefix ([Web Vitals Extension]) to the top-level groups, ie out of table headers
  • Color-coding the metric value by threshold rating
• Individual logs within each group for high-level diagnostic info
  • the LCP element
  • a warning that the LCP was inflated when the tab was loaded in the background (parity with the popup)
  • attribution for each layout shift contributing to CLS as a simplified list of shifted elements and the shift score
  • FID and INP interaction targets and types
• Reverting the table-specific user setting
• Adding usage instructions to the README

[tunetheweb]

@mmocny we good to merge this, or are you in the middle of your updates so woulds rather hold off for a bit?

@gilbertococchi any comments on this?

[mmocny]

Oh damn, I didn't see this and had a very similar patch locally. Let's land this one and I'll rebase.

[gilbertococchi]

This is amazing, +1 to the latest changes with Grouping, I agree that putting the prefix in the table was a workaround and I like the fact that it allowed to have the "Target" as clickable element as well. LGTM