Add ccache option to enable ccache inside the container for acceleration

[tfoote]

There are a few options how this could be implemented.

• Purely intra-container setup (without sharing outside the container)
• Just a volume mount of the ~/.ccache directory (likely using local env redirects)
• Mount a ccache docker container volume for the shared ccache (no host interactions)
• Use some sort of server type integration like sccache: https://github.com/mozilla/sccache or even distcc

This should be clearly documented as only for trusted code due to the potential for cache poisoning.