CLI remove dbHost, dbName, dbUser and dbPass configuration options

[Michiel-s]

Currently mysql database configuration options can be provided via the command line interface.
This is used by:

• PHP.hs for travis check
• Settings.json input file for prototype framework

However, for the prototype framework we're planning to ignore these from the settings.json because database settings are most of the time deployment environment specific. For a local test env you use different settings than for a remote production environement.
As docker is used to build an ampersand prototype image, this image must be different for test and production, because the settings are 'baked' into the image. This is not complying to the "Image Immutability Principle" of container based application design.
See: https://kubernetes.io/blog/2018/03/principles-of-container-app-design/

This issue request removal of the database settings from the Ampersand compiler.

TODOs:

• Adapt prototype framework. -> see Feature/#1070 remove database settings from Ampersand compiler prototype#22
• Adapt Ampersand compiler
• Update documentation. https://ampersandtarski.gitbook.io/documentation/the-command-line-tool and sub pages not needed, because dbHost, dbName, dbUser and dbPass options were not described for compiler v4.x

[Michiel-s]

Done after merging #1121