Purpose of this pull request

After updating the https://developer.adobe.com/commerce/ landing page, we received feedback that their could be better engagement for users as they land on the Getting Started page.

• Moved the "What can I do..." section up and added a "Key features" heading for the shifted content.
• Added an obvious learn more link for GraphQL and Rest, which will also serve to deemphasize SOAP.
• Replaced * with - for unordered lists, per current linter rules.

Staging: https://adobedocs.github.io/commerce-webapi/get-started/

holding this in a draft state until @keharper can give his feedback