New Dockerfile

[vasdommes]

Added Dockerfile to root.

Usage:

docker build . --tag sdpb
docker run sdpb mpirun -n 1 sdpb --help

Major differences from 2.5.1 (see docs/site_installs/sdpb_dev_Dockerfile):

• Self-contained, no need to download images by hand, rename files etc.
• SDPB only, no blocks_3d etc. (TODO create separate bootstrap_bundle?).
• Multi-stage build to reduce image size.
• Based on (recommended by Docker) Alpine Linux instead of Debian => image size 143MB instead of 396MB.
• separate 'test' target allowing to run sdpb tests as follows (will be used e.g. for CI):

docker build . --tag sdpb-test --target test
docker run sdpb-test ./test/run_all_tests.sh mpirun --oversubscribe

[vasdommes]

P.S. I'm going to update documentation and remove old dockerfiles after preparing separate Docker images for blocks_3d and scalar_blocks.