util/docker: Add Dockerfile for Arch Linux

Add a minimal Dockerfile that pre-installs necessary software which is
needed to work with coreboot.

Change-Id: I85f3dc7b28b77989f0f1400d1282ed4b17082f65
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74481
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>

util/docker/archlinux/Dockerfile

@@ -0,0 +1,19 @@
+FROM archlinux:latest
+
+RUN pacman-key --init && \
+	pacman -Sy --noconfirm archlinux-keyring && \
+	pacman-key --populate && \
+	pacman-key --refresh-keys && \
+	pacman -Syu --noconfirm
+
+RUN pacman -S --noconfirm \
+	base-devel \
+	bash-completion \
+	gcc-ada \
+	git \
+	go \
+	htop \
+	neovim \
+	python3 \
+	tmux && \
+	rm -r /var/cache/pacman/pkg/*