common: move default version out of Config

This way we will be able to codegen the default version.

Config.DefaultConfigurationVersion ->
ConfigCommon.defaultConfigurationVersion

Change-Id: Ibcbf08fd77d61a07c83e1e32f0cd67c40ab4cde0
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>