(cherry picked from commit 9d83a203)

Issue #3067645 by greg.1.anderson, Mile23, Mixologic: Add core scaffold assets to drupal/core's composer.json extra field

Issue #2568439 by anchal29, hussainweb, priya.chat, r_sharma08, drupal.ninja03, anil280988, snehi, tedbow, joyceg, amit.drupal, jhodgdon: profiles/README.txt incorrectly states that installation profiles do not 'have any effect on' already running sites

Issue #2115737 by darol100, rhuffstedtler, andythomnz, jemandy, ijf8090, zealfire, er.pushpinderrana, jhodgdon: Make the text in modules, themes, and profiles README.txt files more user-friendly

Issue #1539940 by jwilson3, infiniteluke, mrf, ryanissamson: Fix up README files to encourage good placement of themes, modules, and profiles

Issue #562042 by cburschka, Rob Loach, sun, scor: Added Search for install profiles in sites/[all|site]/profiles folders, and move core profiles into /core/profiles.

#360415 by JohnAlbin: Ship Drupal with a default sites/all/modules and sites/all/themes directory. Hooraycvs diff :D