Docker: update image and optimize for layer caching

Dockerfile

@@ -7,7 +7,7 @@ COPY browser/ /browser
 WORKDIR /browser
 RUN wasm-pack build --release
 
-FROM node:14.16.0 as frontend
+FROM node:16.0.0 as frontend
 COPY package.json yarn.lock /src/
 COPY --from=wasm /browser /src/browser
 WORKDIR /src
@@ -18,14 +18,27 @@ COPY tsconfig.json webpack.config.js jest.config.ts /src/
 COPY templates /src/templates
 WORKDIR /src
 RUN yarn build
+COPY scripts /src/scripts
+RUN /src/scripts/librejs.sh
 
 FROM rust:latest as rust
 WORKDIR /src
-COPY . .
+RUN mkdir src && echo "fn main() {}" > src/main.rs
+COPY Cargo.toml .
+RUN sed -i '/.*build.rs.*/d' Cargo.toml
+RUN sed -i '/.*browser.*/d' Cargo.toml
+COPY Cargo.lock .
+COPY migrations /src/migrations
+COPY sqlx-data.json /src/
+COPY src/tests-migrate.rs /src/src/tests-migrate.rs
+COPY src/settings.rs /src/src/settings.rs
+RUN cargo --version
+RUN cargo build --release
+COPY . /src
 COPY --from=frontend /src/static/cache/bundle /src/static/cache/bundle
 RUN cargo build --release 
 
-FROM debian:buster
+FROM debian:bullseye
 RUN useradd -ms /bin/bash -u 1001 mcaptcha
 WORKDIR /home/mcaptcha
 COPY --from=rust /src/target/release/mcaptcha /usr/local/bin/