Add possibility to navigate pods in history

[tmm360]

Is your feature request related to a problem? Please describe.
Currently it's not possibile to access a previous state of a pod. Users could be interested for example to access a previous state of a document db, when there was a specific document that has been removed later, or a previous state of a specific document. At now, it's not possible.

Describe the solution you'd like
When an user open a pod, or a public pod, it can optionally specific a previous point in time where pod has to be find. In this case, the "versioned" pod can be opened in read-only mode, or could be forked eventually into a new one, with its specific future history. If forks will be possible.