feat: demos & master branch coverage

[artus9033]

Describe your changes

This PR introduces the following:

• added built demos to the source tree
• updated README
  • added Chart.js version compatibility matrix
  • fixed links in README (w.r.t. the reporthere)
  • added ToC
  • updated 'Contributing' section
• added a PR template
• updated tar transient dependency version (npm audit)

Linked issues (if any)

N/A

Checklist before requesting a review

• [x] E2E tests' snapshots (screenshots) are up-to-date
• [x] documentation is up-to-date

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

:exclamation: No coverage uploaded for pull request base (master@d3965c5). Click here to learn what that means.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #133 +/- ## ========================================= Coverage ? 70.21% ========================================= Files ? 1 Lines ? 188 Branches ? 75 ========================================= Hits ? 132 Misses ? 56 Partials ? 0 ```

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