TYPO3 Core

The &no_cache parameter is the number one reason for unneccessarily slowing down a website.

There are better ways to turn off caching for certain parts of a website, therefore the parameter should be removed.

This will require lots of extensions to be changed, therefore I suggest to introduce this change in two steps:
1. Allow disabling of the parameter so that developers can see what would break
2. Finally, enable the parameter by default
(issue imported from #M6547)