Introduce experimental Dockerfile for compose-web-based jobs

ci/docker/compose-web/Dockerfile

@@ -0,0 +1,22 @@
+FROM ubuntu:20.10
+
+ENV LANG='en_US.UTF-8' LANGUAGE='en_US:en' LC_ALL='en_US.UTF-8'
+
+RUN dpkg --add-architecture i386 && apt-get update -yqq && apt-get install -y \
+    curl \
+    git \
+    python3 \
+    python-is-python3
+
+RUN apt-get clean 
+
+RUN mkdir ~/bin
+ENV PATH=~/bin:$PATH
+
+RUN curl https://storage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
+RUN chmod a+x ~/bin/repo
+RUN mkdir androidx-main 
+WORKDIR  androidx-main
+RUN ~/bin/repo init -u https://android.googlesource.com/platform/manifest \
+    -b androidx-main --partial-clone --clone-filter=blob:limit=10M
+RUN ~/bin/repo sync