Dockerfile: use env vars for consistency

Signed-off-by: Lakshya Singh <lakshay.singh1108@gmail.com>

vlsd/Dockerfile

@@ -24,14 +24,16 @@ RUN cd vls && \
 
 FROM --platform=${TARGETPLATFORM:-${BUILDPLATFORM:-linux/amd64}} alpine:3.18 as runner
 
-ARG UID=100
-ARG GID=101
+ARG VLSD_UID=100 \
+    VLSD_GID=101 \
+    VLSD_USER=vls
+ARG VLSD_HOME=/home/${VLSD_USER}
 
 LABEL maintainer.0="Lakshya Singh (@king-11)" \
   maintainer.1="Dev Random (@devrandom01)"
 
-RUN addgroup vls --gid ${GID} --system
-RUN adduser --uid ${UID} --system vls --ingroup vls
+RUN addgroup ${VLSD_USER} --gid ${VLSD_GID} --system
+RUN adduser --uid ${VLSD_UID} --system ${VLSD_USER} --ingroup ${VLSD_USER}
 
 RUN apk update && \
   apk add \
@@ -52,16 +54,16 @@ RUN chmod +x /healthcheck.sh
 
 COPY vlsd2.toml /vlsd2.toml
 
-ENV VLS_DATA=/home/vls/.lightning-signer
-RUN mkdir ${VLS_DATA}
-RUN chown vls:vls ${VLS_DATA}
+ENV VLSD_DATA=/home/vls/.lightning-signer
+RUN mkdir -p ${VLSD_DATA} && \
+    chown ${VLSD_USER}:${VLSD_USER} ${VLSD_DATA}
 
-ENV REMOTE_SIGNER_ALLOWLIST=${VLS_DATA}/ALLOWLIST
+ENV REMOTE_SIGNER_ALLOWLIST=${VLSD_DATA}/ALLOWLIST
 RUN touch ${REMOTE_SIGNER_ALLOWLIST}
 
-VOLUME ["${VLS_DATA}"]
+VOLUME ["${VLSD_DATA}"]
 
-USER vls
+USER ${VLSD_USER}
 
 HEALTHCHECK --interval=10s --timeout=10s --start-period=10s \
     CMD ["/healthcheck.sh"]