@arubislander From my reading of the documentations I couldn't figure out any formal way to configure the Multimedia support in "docker run" command but I did something hackish and got camera working in clickable desktop. Audio devices were already accessible in the docker.
Under by Home directory I found the place where the clickable python scripts are installed.
In there I searched further and found the script "commands/docker/multimedia_support.py"
Here I found the audio device(dev/snd) was already being made accessible to the docker container through the config hard coded here.
So I edited the code in this file, to pass my camera devices also in the key-value list passed into docker_config.volumes.update method.
Then I re-run my app and Voila! camera access started working in my app.
From clickable.log I could see the key-value pairs passed in here are coming out in the docker run command executed while launching app as volumes to be mounted(-v arguments).
Thanks for your support.

@arubislander I'm not sure. I suspect the name of video device can change for different environments. Some environments may not even have a camera, and I haven't yet tested for negative side effects of putting a non-existing device there.
I'm thinking I may have to write some additional code to detect camera devices in the environment to make it into a PR suitable for all users. I'll try to figure out though.

Thanks for the encouragement