Build webapp assets during Docker build instead of checking them into git

[benoit-nexthop]

This closes #609

• Add webapp build stage to Dockerfile and Dockerfile.build-static using node:lts-alpine
• Move build-webapp.sh to scripts/ directory
• Add .dockerignore to exclude node_modules and reduce build context
• Update .gitignore to exclude compiled webapp assets
• Remove compiled webapp assets from repository, keeping it up to date was a constant source of conflict and doing this was bad practice generally anyway

[gabriel-samfira]

I've been meaning to address this for a while, but have had very little time lately. So thanks!

Just a few comments for the build-static bit. Let me know what you think

[gabriel-samfira]

This Dockerfile was initially written to be built once and reused many times by just creating a new temporary container from it and running the build-static.sh script. But given that we might need to also build and copy the webapp now, I think we can expand it a bit more and just run docker build to get the static binary. See bellow comments.

[gabriel-samfira]

We can replace this with

Suggested change

	CMD ["/bin/sh"]
	ARG GARM_REF=""
	ENV GARM_REF=${GARM_REF}
	RUN /build-static.sh
	# Stage 3: Export only the binaries
	FROM scratch AS export
	COPY --from=builder /build/output/ /
	CMD ["/bin/sh"]

See the Makefile comment for the last bit.

[gabriel-samfira]

Then this section can be replaced with something like:

build-static: ## Build garm statically
	@echo Building garm
	mkdir -p build
	$(IMAGE_BUILDER) build $(EXTRA_ARGS) \
		--build-arg GARM_REF=$(GARM_REF) \
		--output type=local,dest=$(PWD)/build \
		--target=export \
		-f Dockerfile.build-static .
	@echo Binaries are available in $(PWD)/build