fix(build): enable build from source on a given version of UHD. For the moment, in all docker images, v3.15.0.0 is used

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

docker/Dockerfile.ran.ubuntu18

@@ -29,8 +29,9 @@
 FROM ubuntu:bionic AS ran-build
 ARG NEEDED_GIT_PROXY
 ENV DEBIAN_FRONTEND=noninteractive
-ENV TZ=Europe
-RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
+ENV TZ=Europe/Paris
+ENV BUILD_UHD_FROM_SOURCE=True
+ENV UHD_VERSION=3.15.0.0
 
 #install developers pkg/repo
 RUN apt-get update && \