Rework module system

[webmaster442]

Module implementation is now based on interfaces, bus should be changed to an abstract class with the following extensions to the current system:

• Default tile color provider, that can be overriden. Default provider algorithm should calculate color from module name
• CanShow property, that can be overriden to check if some required criteria is met. (Eg: only show git-cmd as a command line, when git is installed)