docs: add quick links to docs pages for small screens and add section table of contents indexes

[tmorehouse]

Describe the PR

Adds a quick links TOC to the top of each /docs page for small screens (when right side TOC is not visible)

Should provide a better user experience for mobile / small-screen users

To do:

• create new quick-links docs component (h2 tags only)
• emit TOC data on created rather than mounted
• Emit TOC data pre-generated
• Instead of redirect to first page entry, render a section TOC
• Pre-build TOC data as a JSON file during Nuxt generate/build process (rather than on mount) for docs performance reasons
• cache previous TOC generation results for docs performance reasons
• Add breadcrumbs to docs pages

PR checklist

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Enhancement
• ARIA accessibility
• Documentation update
• Other (please describe)

Does this PR introduce a breaking change? (check one)

• No
• Yes (please describe)

The PR fulfills these requirements:

• It's submitted to the dev branch, not the master branch
• When resolving a specific issue, it's referenced in the PR's title (i.e. [...] (fixes #xxx[,#xxx]), where "xxx" is the issue number)
• It should address only one issue or feature. If adding multiple features or fixing a bug and adding a new feature, break them into separate PRs if at all possible.
• The title should follow the Conventional Commits naming convention (i.e. fix(alert): not alerting during SSR render, docs(badge): update pill examples, fix typos, chore: fix typo in README, etc). This is very important, as the CHANGELOG is generated from these messages.

If new features/enhancement/fixes are added or changed:

• Includes documentation updates (including updating the component's package.json for slot and event changes)
• Includes any needed TypeScript declaration file updates
• New/updated tests are included and passing (if required)
• Existing test suites are passing
• The changes have not impacted the functionality of other components or directives
• ARIA Accessibility has been taken into consideration (Does it affect screen reader users or keyboard only users? Clickable items should be in the tab index, etc.)

If adding a new feature, or changing the functionality of an existing feature, the PR's
description above includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)

[codecov]

Codecov Report

Merging #4145 into dev will not change coverage.
The diff coverage is n/a.

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##              dev    #4145   +/-   ##
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  Coverage   99.86%   99.86%           
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  Files         237      237           
  Lines        4463     4463           
  Branches     1259     1259           
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  Hits         4457     4457           
  Misses          5        5           
  Partials        1        1

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[jacobmllr95]

@tmorehouse Good idea, but I think it should be moved before the initial section.

[tmorehouse]

@jackmu95 yeah... I was thinking the same, although need to break the readme file up with a RegExpr first. Or place it after the H1 (which might be easier).

Though about making it a collapse or a <details> as well

[jacobmllr95]

@tmorehouse I implemented a simple re-positioning logic on mount.
The positioning is way better now IMHO but I had to hide it initially and show it after the re-positioning to make it not to distracting.

[tmorehouse]

@jackmu95 added in breadcrumbs at the top of each docs page