Ability to access files outside of action dir during build phase

[davidferlay]

Current

• During build, Dockerfile cannot access any file located outside of action dir

Expected

• During build, Dockerfile should be able to access any file located outside of action dir
• Example use cases:
  • Use a shared library
  • Use values from a group_var or vault file

Todo

• Expand build context to be able to see files outside of action dir

[lexbritvin]

Impossible to do because of how image build works in Docker and other tools.
Probably we may consider symlinks and see if Docker supports it in docker build.