Task:
Allow the users to select between showing only their, only the conflicting, or both changes in the left text field.
This means:

• Below the subtitle of the "Conflicting Changes" section there is a selection option which changes are shown
  • Title: Show changes
  • Options: mine, currently published, both
  • The option titles should have a background color that corresponds to the change background colors
• When a user selects mine, only their changes are being shown in the diff parts. When a user selects currently published, only the other party's changes are shown. Both is the default
• Ideally, there is a version without page reload for people with js, and a version with page reload for people without js.

Mock:
See also the mock for a general idea.

Background:
This is part of fulfilling wish #1 of the German-speaking community wishlist 2015 (T143823).
The solution is a result of on-wiki discussion and Wikimania 2016 sessions and testings, as well as feedback we received to the prototype.