Fix source file name path stripping in Doxygen

Currently the STRIP_FROM_PATH option is not set, as a result the full
path of source files is "leaked" into the generated HTML. For example,
this documentation page:

http://docs.pointclouds.org/1.9.1/voxel__grid__occlusion__estimation_8h_source.html

Has the following title:

<title>Point Cloud Library (PCL): /__w/1/s/filters/include/pcl/filters/voxel_grid_occlusion_estimation.h Source File</title>

This is an absolute path on Azure Pipelines worker.

We already have path stripping set up properly in STRIP_FROM_INC_PATH,
so this commit just copies the same paths over.

Additionally indentation is fixed in the generated Doxyfile by using
spaces instead of tabs.

cmake/pcl_targets.cmake

@@ -834,7 +834,7 @@ macro (PCL_ADD_DOC _subsys)
     endif()
     if(NOT "${dependencies}" STREQUAL "")
       set(STRIPPED_HEADERS "${PCL_SOURCE_DIR}/${dependencies}/include")
-      string(REPLACE ";" "/include \\\n\t\t\t\t\t\t\t\t\t\t\t\t ${PCL_SOURCE_DIR}/"
+      string(REPLACE ";" "/include \\\n                         ${PCL_SOURCE_DIR}/"
              STRIPPED_HEADERS "${STRIPPED_HEADERS}")
     endif()
     set(DOC_SOURCE_DIR "\"${CMAKE_CURRENT_SOURCE_DIR}\"\\")

doc/doxygen/CMakeLists.txt

@@ -33,7 +33,7 @@ if(DOXYGEN_FOUND)
   endif()
 
   set(STRIPPED_HEADERS "${PCL_SOURCE_DIR}/${PCL_MODULES_NAMES}/include")
-  string(REPLACE ";" "/include \\\n\t\t\t\t\t\t\t\t\t\t\t\t ${PCL_SOURCE_DIR}/" STRIPPED_HEADERS "${STRIPPED_HEADERS}")
+  string(REPLACE ";" "/include \\\n                         ${PCL_SOURCE_DIR}/" STRIPPED_HEADERS "${STRIPPED_HEADERS}")
   set(DOC_SOURCE_DIR "\"${PCL_SOURCE_DIR}\"\\")
   file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/html")
   set(doxyfile "${CMAKE_CURRENT_BINARY_DIR}/doxyfile")

doc/doxygen/doxyfile.in

@@ -25,7 +25,7 @@ ABBREVIATE_BRIEF       = "The $name class" \
 ALWAYS_DETAILED_SEC    = NO
 INLINE_INHERITED_MEMB  = NO
 FULL_PATH_NAMES        = YES
-STRIP_FROM_PATH        =
+STRIP_FROM_PATH        = @STRIPPED_HEADERS@
 STRIP_FROM_INC_PATH    = @STRIPPED_HEADERS@
 SHORT_NAMES            = @SHORT_NAMES@
 JAVADOC_AUTOBRIEF      = YES