Add dockerfile for aarch64

Add dockerfile for aarch64

This commit allows building the functest image on aarch64 jenkins slave
The changes from the x86 dockerfile are:
- pull the aarch64 ubuntu image for docker
- add libjpeg-dev to the dependency list (needed for Pillow package)
- add bundler to gem because the version of ruby that is found is
  1.9.3p484 instead of 1.9.3-p551

 /usr/local/rvm/rubies/ruby-1.9.3-p551/lib/ruby/site_ruby/1.9.1/
 rubygems/core_ext/kernel_require.rb:55:
 in `require': cannot load such file -- bundler  (LoadError)

- configure nokogiri to use system libraries because the packet
  used an outdated config.guess file
- get the npm packet for arm64; since there is no deb for it,
  I extracted the needed files from the arhives in the repo

Ported https://gerrit.opnfv.org/gerrit/#/c/27971/ to this file

Change-Id: Icedbc54a685534bde14769182250cd098f24a26a
Signed-off-by: Cristina Pauna <cristina.pauna@enea.com>