Make Colored Workflow-State Switchable

[sarn0ld]

Summary
As a website admin I want to be able to configure the workflow states to be displayed in black color, so that the styling of the sidebar meets the requirements of my website's styling.

Acceptance Criteria

• It's done when there is a sidebar control panel.
• It's done when there is an option in the control panel to "enable colors for workflow states".
• It's done the option is disabled by default
• It's done when the enabled option enables the colored workflow states like we have now
• It's done when the disabled option shows just plain black text and icon for workflow states, like we do for every other item in the sidebar

Technical Notes
My suggestion: Create a registry entry connected to a setting in a (new) sidebar control panel.

Additional notes
With Issue #19 and #7 we introduced different colors for the different workflow states. This should be switchable to just display black text + icon.