feat/caching (#5333)

Enable the building and pushing of docker containers on master, and then using them as a cache base in prs.

This should massively reduce the build times, and the load we are placing on other projects servers.

Depends on #5330

Co-authored-by: Darragh Elliott <me@delliott.net>
Reviewed-on: #5333
Co-authored-by: delliott <delliott@fsfe.org>
Co-committed-by: delliott <delliott@fsfe.org>

pre-commit.Dockerfile

@@ -38,11 +38,11 @@ WORKDIR /website-source-during-build
 
 # Copy the pyproject and build deps
 # Done in a seperate step for optimal docker caching
-COPY ./pyproject.toml ./uv.lock .
+COPY ./pyproject.toml ./uv.lock ./
 RUN uv sync --no-install-package fsfe_website_build --group dev
 
 # Copy entrypoint
-COPY pre-commit.entrypoint.sh .
+COPY pre-commit.entrypoint.sh ./
 
 # Set the workdir
 WORKDIR /website-source