Enable multiarch for docker

Dockerfile

@@ -1,11 +1,11 @@
-FROM rust:1.68-alpine3.17 AS bin-builder
+ARG base="alpine:3.17"
 
-# Install dependencies
+FROM ${base} AS bin-builder
-RUN apk add --no-cache openssl-dev musl-dev
 
+RUN apk add --no-cache cargo openssl-dev musl-dev
 # This will build all dependencies and store them in docker's cache.
 # This way, it won't be necessary to recompile everything everytime
-# Disable static linking, see: https://users.rust-lang.org/t/sigsegv-with-program-linked-against-openssl-in-an-alpine-container/52172
+# It also disables static linking, see: https://users.rust-lang.org/t/sigsegv-with-program-linked-against-openssl-in-an-alpine-container/52172
 COPY backend/Cargo.toml .
 COPY backend/Cargo.lock .
 RUN echo '[[bin]]' >> Cargo.toml && \
@@ -15,31 +15,28 @@ RUN echo '[[bin]]' >> Cargo.toml && \
     RUSTFLAGS='-C target-feature=-crt-static' cargo build --release 
 RUN rm cache.rs && \
     rm Cargo.toml
-
 # Build wimple-wkd
 COPY backend/Cargo.toml .
 COPY backend/src src
 RUN RUSTFLAGS='-C target-feature=-crt-static' cargo build --release
 
 
-FROM node:19-alpine3.17 AS webpage-builder
+FROM ${base} AS webpage-builder
 
-# Build website
+RUN apk add --no-cache npm
 COPY website .
 RUN npm install -g pnpm && \
     pnpm install && \
     pnpm run build
 COPY assets assets
-
 # Move website in templates folder
 RUN mv dist assets/webpage
 
 
-FROM alpine:3.17
+FROM ${base}
 
-# Put everything together
+# The final image uses user `wkd` for added security
-# It uses user `wkd` for added security
+# It also installs libgcc, because the executable is dynamically linked to it
-# Install libgcc, because the executable is dynamically linked to it
 WORKDIR /wkd
 RUN apk add --no-cache libgcc && \
     adduser --no-create-home --disabled-password wkd && \