New feature version
- Upgraded ACTS to v3.00.0
- Added spack package overrides directly to this repo for transparency
- Refactored CI:
- Got rid of staging step which was somewhat redundant
- Streamlined CI script to get rid of all almost duplicate pipeline steps
- Use rules to automatically build on master, develop, tags and merge-requests
- Detect if we can use the docker cache, or if we need to start over clean.