Added docker support for bambucam

[DavidGitter]

Added Docker Support

By adding a Dockerfile, start-script and a compose, you can now easily setup bambucam as container running on a docker host. You simply have to configurate the settings of the Dockerfile/docker compose and can start the webserver.
Also i provided the Dockerfile build instructions if you want to build the image for yourself.

Changes

• Added .gitignore to ignore env-variables in file and the bambulib
• Added the dockerfile to build the bambucam image
• Added a start.sh called by the image which contains a loop for starting the stream if its ready
• Added a docker-compose for easy deployment
• Updated the README with the new docker instructions