DS-1689 Spatial Indexing and Querying

This request implements the following:

1. Introduces a new input-type "location" for submitting an item's bounding box using a map.
An example is commented at input-forms.xml

2. Enables Spatial Indexing and quering in Lucene. The user has to specify the spatial metadata field in config.cfg following by ":location" flag

3. Enables Spatial Indexing and quering in Solr. For that reason a new spatial field Type was added in solr schema. The user has to specify the spatial metadata field in discovery.xml. 

Also, there is an implementation in XMLUI for mirage theme.

For making visible the map it needs to export OpenLayers 2.12 API (http://openlayers.org/download/) in xmlui/static/js folder and comment out "display:none" command in style.css at line 1405.

Also jts-1.8.jar must be present at lib folders 
It is necessary to specify a URL that is a WMS (Web Map Service). For example I use another WMS which i specify in spatial.js file 
var wms = new OpenLayers.Layer.WMS( "OpenStreetMaps WMS", "http://ows.terrestris.de/osm/service", {layers: 'OSM-WMS'});
Althought maybe it is possible to move this URL in another settings file (e.g. dspace.cfg)