[Starlingx-discuss] [Build] Removing Makefile for docker base image creation.

[Cordoba Malibran, Erich]

Hi all, 

Trying to fix this bug[0], I realize that the Makefile used to create
the docker build base image can be removed in favor of the tb.sh
script.

I'm proposing this change[1] that will help to enable building in non-
ubuntu systems. Also, I'm updating the documentation[2].

This change could break some workflows, please let me know if you have
any objection. 

Best regards. 

-Erich


[0] https://storyboard.openstack.org/#!/story/2002560
[1] https://review.openstack.org/#/c/637944/2
[2] https://review.openstack.org/#/c/637946/