chore(CMake): make GeographicLib optional for LtsCoordTrans to allow partial configure during migration

Lts/Common/LtsCoordTrans/CMakeLists.txt

@@ -5,17 +5,22 @@
 # Created by Christian Ehrlicher, SLSE, 2016-08-31
 #
 
-FIND_PACKAGE(GeographicLib REQUIRED)
+FIND_PACKAGE(GeographicLib)
 NGL_ADD_LIBRARY2(LtsCoordTrans WS AAR SV HLA SHARED
   lts_coord_trans.h
   lts_coord_trans.cpp
 )
 NGL_TARGET_LINK_LIBRARIES(LtsCoordTrans
   PRIVATE
-    GeographicLib
-  PUBLIC
     Qt5::Core
 )
+if (GeographicLib_FOUND)
+  NGL_TARGET_LINK_LIBRARIES(LtsCoordTrans
+    PRIVATE GeographicLib
+  )
+else()
+  message(STATUS "GeographicLib not found; building LtsCoordTrans without it")
+endif()
 NGL_TARGET_INCLUDE_DIRECTORIES(LtsCoordTrans
   PUBLIC
     ${CMAKE_CURRENT_SOURCE_DIR}/../