Encapsulate SchemaPath creation

When we look at actualPath, we always want the SchemaPath -- so let's do
precisely that.

Change-Id: Ibe65adfb841cd1422b3fbc6945b3a87a3cdce62d
Signed-off-by: Robert Varga <rovarga@cisco.com>
Introduce moduleQName for sharing

If we stire namespace/revision/prefix in a QName, we are able to create
related QNames using a utility method, which will automatically share
the resulting QNameModule.

Change-Id: I53fbf10cf853cb3a4b265fd1f9823f604f148e73
Signed-off-by: Robert Varga <rovarga@cisco.com>