Dockerfile: add labels, cleanup since multi-stage

Dockerfile

@@ -1,16 +1,19 @@
 FROM ubuntu:20.04
-LABEL maintainer="https://github.com/pdiakumis"
+LABEL org.opencontainers.image.authors='[email protected], [email protected]' \
+      org.opencontainers.image.description='Personal Cancer Genome Reporter (PCGR)' \
+      org.opencontainers.image.source='https://github.com/sigven/pcgr' \
+      org.opencontainers.image.url='https://github.com/sigven/pcgr' \
+      org.opencontainers.image.documentation='https://sigven.github.io/pcgr' \
+      org.opencontainers.image.licenses='MIT'
 
 ARG MINI_VERSION=4.11.0-0
 ARG MINI_URL=https://github.com/conda-forge/miniforge/releases/download/${MINI_VERSION}/Mambaforge-${MINI_VERSION}-Linux-x86_64.sh
 
 # install core pkgs, mambaforge
 RUN apt-get update && \
     apt-get install --yes --no-install-recommends \
-    bash bzip2 curl git less vim wget zip ca-certificates && \
+    bash bzip2 curl less wget zip ca-certificates && \
     apt-get clean && \
-    rm -r /var/lib/apt/lists/* && \
-    rm -r /var/cache/apt/* && \
     curl --silent -L "${MINI_URL}" -o "mambaforge.sh" && \
     /bin/bash mambaforge.sh -b -p /opt/mambaforge/ && \
     rm mambaforge.sh