Add VERSION file with Kimchi version

In order to run Kimchi outside a git repository, like a tar/zip file, the
VERSION file is needed. Otherwise, the user will not be able to run autogen.sh
Also prioritize git tag instead of VERSION file content and update VERSION file
on each "make dist".

Signed-off-by: Adam Litke <agl@linux.vnet.ibm.com>
Signed-off-by: Aline Manera <alinefm@br.ibm.com>
Signed-off-by: Crístian Viana <vianac@linux.vnet.ibm.com>