version rights model need to be clarified

The current rights model about version is confusing. We're defining two permissions "Version" and "ReadVersion".
These two versions are include in "Read" permission. Also, "ReadVersion" is aliasing "Version".
We don't want to keep this.
Here is what we want to be in place instead.

Let say that

• we have the two basic permissions : READ_VERSION (can read a version) and WRITE_VERSION (can create a version)
• we have the composed permission VERSION that composes READ_VERSION and WRITE_VERSION
• and finally the READ permission compose the READ_VERSION permission

If we update the security checks for using this model, we're done.