Clearly explain differences between Drupal CMS and Drupal core on Downloads page

Problem/Motivation

Seems like Drupal CMS is now the default "download" on https://new.drupal.org/download.

The "Get started with Drupal" block is "hidden" only on the bottom of the page. In the "Start Developing" block, there is no explanation for users to make a decision, which one should they use. Based on standard users behavior, only a few will scroll down to the "Get started with Drupal" block, because it is the last block on the page.

I suggest that we move the "Get started with Drupal" block to the top and combine it with the "Start Developing" block, so that users have complete information when making decisions.

Steps to reproduce

Visit https://new.drupal.org/download
See that there is no description in "Start Developing" block to make a decision which system to use

Proposed resolution

Move the "Get started with Drupal" block to the top and combine it with the "Start Developing" block, so that users have complete information when making decisions.

Remaining tasks

User interface changes

API changes

Data model changes