Version build images

Related to omnibus-gitlab#2106 (closed)

1. Rename Dockerfiles to follow Dockerfile_OSName_OSVersion
2. Rename job names to reflect above change
3. Introduced BUILD_REVISION variable to hold revision count Use commit tags instead.
4. Removed rpi_wheezy image from the build list, which is no longer needed. For backports, the existing image will work.
5. Used NodeJS binaries instead of packages
6. Used correct repo for OpenSUSE 42.1