Make the colors and the ticks of the patient dashboard graphs configurable

This is associated to TRAC-2036 ticket.

1) The patient dashboard display's critical regions and abnormal regions in the graph based on the upper limits mentioned in the concept for which the graph is plotted against. These regions are color coded. We need to make the colors configurable. preferably a part of global_property table.

2) The X axis of the graph is currently set to display months. This should also be a configurable property.