Make it a bit easier to get started by connecting to mainnet.
While here, shrink the size of our image further by squashing layers in
a final stage of the build. This gets us down from ~612MB to ~530MB.
The Docker base image is changed from alpine to bullseye-slim. It allows
copying node_modules from build stage directly. The resulting image size
is also reduced because it doesn't need build tools for installing npm
packages.
Our previous attempts to fix the build in 50cfacd5 and 1c932091 didn't
work because we had a locally cached layer which lead to an older
version of Turbo being used, which didn't suffer from this bug.
The workaround (for now) is to pin to 1.7.0 explicitly when installing
`turbo` in the Docker build step (which previously wasn't using the
version listed in `package.json`).
* chore: add Dockerfile to build container
* chore: use multi-step build process to reduce size by 500 MB
* chore: install production deps only to reduce size by ~ 200 MB
