Update README

Verified the MR5, still more formatting is required here as per README.MD Template -> https://www.drupal.org/docs/develop/managing-a-drupalorg-theme-module-or... →
like TOC is missing, unnecessary lines after the title.

Following feedback from #5:

• TOC is optional, but can be added;
• Markdown best practises requires you to add blank lines before and after titles: https://www.markdownguide.org/basic-syntax#heading-best-practices. It even says it in Drupal's documentation.

Please review. Addressed changes in the MR1. Thanks.

Thanks!

I have the same feedback here as on 📌 Update description on settings page Needs work

also likely it should still be called Configuration instead of Getting Started according to https://www.drupal.org/docs/develop/managing-a-drupalorg-theme-module-or... → README sections

Applied feedback from #9.