Allow complete scripted configuration via opensubmit-web

[troeger]

Currently, only a subset of the possible options in settings.ini are supported by opensubmit-web configcreate. The command line tool should be extended to support all OpenSubmit web application settings. This should be supported by some smartness, such as configuring LOGIN_GOOGLE=True when the credentials are provided.

Given the use case of Docker, it might be also good to have on option for fetching all settings directly from environment variables.

[troeger]

See a33cb27