Allow different page content per channel with the same slug

[dbalabka]

Currently, it i possible to show the same page content on different channels. However, there is no possibility to customize the page content per channel. For example, Terms of Condition can be different how ever, we would like to keep the slug. Creating a new page with the same slug that is availble under different channel is not possible because slug is required to be unique acorss language and page, but must be the same across channels.