NDVI statistics changes

* Add a simple jQuery widget to select NDVI dekad from availaibles decads like mapstore NDVI_selector (jquery-mapstore-ndvi-selector.js)
* Changes on geobatch configuration to load DB correctly
* Fix boot on geobatch with 'mvn jetty:run' removing duplicated file loading (applicationContextGBSecurity.xml)
* Add new utilities to DekadUtils and a test for it.