Add write support for facilities.xml

[gac55]

Facility information is currently present within the plans.xml output.

There are some applications which make use of a simplified summary facilities.xml output, which is defined as:

A Facility is a (Basic)Location ("getCoord") with an Id ("getId") that is connected to a Link ("getLinkId").

As per this

[gac55]

file dtd - http://www.matsim.org/files/dtd/facilities_v1.dtd

[gac55]

A workaround for this is to use MATSim itself to extract facilities from the plans output and write facilities. There are some options, requiring consideration and clarification that our method for facility sampling is correctly understood by MATSim.

Speaking with @Theodore-Chatziioannou , we believe that onePerActivityLocationInPlansFile is appropriate.

The configuration in question:

<module name="facilities" >
		<!-- This defines how facilities should be created. Possible values: none fromFile setInScenario onePerActivityLinkInPlansFile onePerActivityLinkInPlansFileExceptWhenCoordinatesAreGiven onePerActivityLocationInPlansFile  -->
		<param name="facilitiesSource" value="onePerActivityLocationInPlansFile" />
		<!-- A prefix to be used for auto-generated IDs. -->
	</module>