Rewrite 4.3 Version subsets

[brechtvdv]

First tell "why" you would be making version subsets, because an eventstream in itself is versioned, so why make subsets?

In order to indicate you only keep 1 specific version, e.g., the latest, in your stream
-> 1 specific version of what?
-> 1 specific version for every object

What's the definition of "ldes:amount"? numberOfLatestVersionsPerObject?

How do we tackle other use cases, e.g., what if you only keep the versions between a certain time window and region?

[pietercolpaert]

Fixed dafe3a6