chore: update Dockerfile and build script to support custom bin and lib path

[nowooj]

Summary

Chain base images may put binaries in different paths. This change lets you set binary and library paths per chain in versions.yaml without adding a separate Dockerfile.
Fixes gaia images where the binary lives in /usr/local/bin and was not included when using the shared Dockerfile (which only copied /bin).

Changes

1. docker/chains/Dockerfile

• Add ARG BIN_PATH=/bin and ARG LIB_PATH=/lib
• Use ${BIN_PATH} and ${LIB_PATH} in COPY --from=source
• Use explicit ENV form: ENV PACKAGES="curl make bash jq sed" (avoids LegacyKeyValueFormat warning)

2. docker/chains/build-docker-chains.sh

• Read bin_path (default /bin) and lib_path (default /lib) from versions.yaml
• Pass them to docker buildx build as --build-arg BIN_PATH and --build-arg LIB_PATH

3. docker/chains/versions.yaml

• Add bin_path: /usr/local/bin for gaia

Usage

For other chains with different paths, add the options in versions.yaml only:

  - name: some-chain
    base: ghcr.io/...
    bin_path: /usr/local/bin   # optional; default is /bin
    lib_path: /usr/lib         # optional; default is /lib
    tags:
      - v1.0.0