Enable revisions by default

Problem/Motivation

Revisions are not enabled by default in Drupal for both new content type and the article / page content types added by the standard install profile. Revisions are a good practice so should be default. I would go as far as saying they should not be optional, but we'll leave that for Drupal 8.1.x

Proposed resolution

Enable revisions by default when creating a new content type, and also for the article and page content types added by the standard install profile.

Remaining tasks

Needs a beta evaluation update to include what revisioning bugs, if any, would now be a part of the out of the box experience.

Signoffs

• Product manager: @webchick seemed to be in favor of this change in #21.
• Entity Field API: @berdir said this change would be okay (see #22)

User interface changes

"Create new revision" checkbox is checked by default.
Change record - https://www.drupal.org/node/2491507 →

API changes

None

Beta phase evaluation