Allow BuildFlags: Buildflags: flag:key to pass an arg

Allow BuildFlags: Buildflags: flag:key to pass an arg

cherry-pick queyconfig only.

From b70ff4d443ecb83c0c47f935a301c44dec3aad0e Mon Sep 17 00:00:00 2001
From: Michael Schroeder <mls@suse.de>
Date: Mon, 19 Oct 2020 16:02:59 +0200
Subject: [PATCH] Support ENV and ARG in Dockerfile

Allow BuildFlags: dockerbuildarg:key=value to pass an arg
to the build command.
---
 Build/Docker.pm     | 61 +++++++++++++++++++++++++++++++++++++--------
 build-recipe-docker | 14 +++++++++--
 queryconfig         |  5 ++++
 3 files changed, 68 insertions(+), 12 deletions(-)

Change-Id: I96bade8f06088d11ccb2f7c57dee5449876537a0
Signed-off-by: Hyunggi Lee <hyunggi.lee@samsung.com>