[install_man] install man to share/man ()

Merging branch 'install_man'  into 'main'.

See merge request !1907

cmake/BornAgain/Directories.cmake

@@ -92,7 +92,7 @@ set(destination_include ${destination_root}include/${destination_suffix}/)
 set(destination_share ${destination_root}share/${destination_suffix}/)
 set(destination_examples ${destination_share}Examples/)
 set(destination_images ${destination_share}Images/)
-set(destination_man ${destination_share}man/man1)
+set(destination_man ${destination_root}share/man/man1)
 
 list(APPEND dstIds bin lib include share examples images man)