Legend in dynamic part

[LiciaFaenza]

Change the map legend of the shakemap at SA0.3, 1.0 and 3.0 seconds in the dynamic part to match those in the static part.

[amichelini]

this is to let you know that in order to sort out the issue it is important to have the legends of the types of maps that we generate.
The simplest solution is that shakemap generates the legend files for all the intensity measurements (imt). I have just submitted a new issue to the usgs shakemap (https://github.com/usgs/shakemap/issues/1215).