[docs_only] Add note about shared drives in Docker for Windows
[docs_only] Add note about shared drives in Docker for Windows

Closes #454, follows up #438.

poldracklab/mriqc,poldracklab/mriqc,oesteban/mriqc,oesteban/mriqc,oesteban/mriqc,poldracklab/mriqc,oesteban/mriqc,poldracklab/mriqc