Document our interpretation of Semver

[micbar]

Description

We do Semver

SemVer itself only talks about APIs.

This leaves some room for interpretation, which can create confusion and uncertainty.

Tasks

We need to document how we realize Semver.

[mmattel]

We should note that info in the readme of the ocis repo first and then copy to where ever it is necessary in the admin docs. The information must be consistent on both sides.