Files Lifecycle Document improvements

[voroyam]

WHAT Needs to be Documented?

A rewrite of the things we have documented

WHERE Does This Need To Be Documented (Link)?

https://doc.owncloud.com/server/10.7/admin_manual/enterprise/file_management/files_lifecycle.html#setting-upload-times-for-existing-files

WHY Should This Change Be Made?

Because of this:

This tip after tip after tip creates a feeling that we don't write our documentation with thought and purpose but pile on info as we go.