Add option to configure memory limit

[nflaig]

Previous network specific packages allowed to configure the --max-old-space-size value via the advanced editor but this is no longer possible. We need to ensure it is always possible for a user to quickly adjust this value if needed without requiring a new package release.

This needs to be applied to the node binary, see https://github.com/dappnode/DAppNodePackage-Lodestar/blob/dbbe28419591453a9c6d09c40f4aaa579d47bb9e/beacon-chain/entrypoint.sh#L37

And set on the docker compose file, see https://github.com/dappnode/DAppNodePackage-Lodestar/blob/dbbe28419591453a9c6d09c40f4aaa579d47bb9e/docker-compose.yml#L24