[hitl] rewrite support for hardware in the loop simulation (#3146)

- old way (based on ins_vectornav) is not supported anymore
- directly send sensor data and receive commands with a dedicated link
- examples with USB link for better results
- update sphinx documentation
- compilation in a single build

conf/modules/gps_nps.xml

@@ -17,7 +17,7 @@
   </header>
   <init fun="gps_nps_init()"/>
   <periodic fun="gps_nps_periodic_check()" freq="1." autorun="TRUE"/>
-  <makefile target="nps|hitl">
+  <makefile target="nps">
     <file name="gps_sim_nps.c"/>
     <define name="GPS_TYPE_H" value="modules/gps/gps_sim_nps.h" type="string"/>
     <test>