TYPO3 Core

Currently when updating an extension, the extension is overwritten.

Now it would be nice to have the old extension archived into a different directory (f.e. typo3conf/ext_archive)

Advantages:

• making it possible to easily jump back to the old version if something is not working anymore
• easily jump back if the admin didn't notice that the extension was changed and now stuff is not working anymore
• in an update script it would be possible to determine which version of an extension was installed before and which actions need to be executed to update data and the like with minimal effort

(issue imported from #M11402)