initial Dockerfile along with changes required for setting locale correctly inside Docker container.

Dependencies such as jefferson are now python3 only and python2 is no
longer supported, as it appears all our dependencies have python3
versions it should be safe to drop python2 support.

Jefferson has moved to Python 3. This requires changes to `deps.sh`

"/etc/os-release" is more common than "/etc/lsb-release"
source: https://gist.github.com/natefoo/814c5bf936922dad97ff

Version 1.1 of cramfs does not build anymore with glibc 2.28 because
since this version glibc no longer includes <sys/sysmacros.h> from
<sys/types.h>, and therefore <sys/sysmacros.h> must be included
explicitly when major()/minor() are used.

To fix this issue, use new upstream project which includes
https://github.com/npitre/cramfs-tools/commit/434aabd67a39165ee0750c0e0d25213bf2ec8fa5

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

2.Seperate dependencies now used for ubuntu 17
	- cramfsprogs is not in default repos for 17

Due to the way we check for missing commands, errexit will cause the script to quit too soon.