Added status parameter to declare state of application

[madelen-at-work]

Describe your changes

Added a status parameter that can be read via param.cgi. It signals the current state of the application, i.e. is it running, is dockerd running or what prevents dockerd from running.

Checklist before requesting a review

• I have performed a self-review of my own code
• I have verified that the code builds perfectly fine on my local system
• I have added tests that prove my fix is effective or that my feature works
• I have commented my code, particularly in hard-to-understand areas
• I have verified that my code follows the style already available in the repository
• I have made corresponding changes to the documentation