Documentation on importing in Docker out of date

[j-hudecek]

The docs on importing stuff in Docker

https://github.com/cBioPortal/cbioportal/blob/master/docs/deployment/docker/import_data.md

still use the old path /cbioportal/core but the new dockers have core in / and don't ship src so the command to import stuff should be

bash -c 'cd /core/scripts/ && ./importGenePanel.pl --data ...

The core package also doesn't include the test data so the whole document needs to be revised. Or test data added back? Or docker image built with core in its place? Or should this be solved as part of #10734 ?