[FEA] Update Docker image to resolve permission issue

Is your feature request related to a problem? Please describe.
Follow up change/comments for:

• https://github.com/Project-MONAI/monai-deploy-app-sdk/pull/168
• https://github.com/Project-MONAI/monai-deploy-app-sdk/pull/168#discussion_r725550615
• https://github.com/Project-MONAI/monai-deploy-app-sdk/pull/168#discussion_r725551221
• https://github.com/Project-MONAI/monai-deploy-app-sdk/pull/168#pullrequestreview-775615834

Need to figure out the general solution.

Describe the solution you'd like

The general solution could be involved in using a tool like gosu (https://github.com/tianon/gosu) and changing folder permission at launch time.

May can refer to Jupyter notebook docker’s solution (https://github.com/jupyter/docker-stacks).

This is how Jupyter notebook docker workaround the user/permission issue.

• https://jupyter-docker-stacks.readthedocs.io/en/latest/
• https://github.com/jupyter/docker-stacks/blob/master/base-notebook/Dockerfile

It calls this script to fix permission settings:

• https://github.com/jupyter/docker-stacks/blob/master/base-notebook/start.sh#L67

Another info: Kubeflow serving Jupyterlab

• https://www.kubeflow.org/docs/components/notebooks/container-images/