Prune the source tree to the Release 2 build closure

Keep only what the Release 2 scope (46 targets) compiles and the build
pipeline needs, derived from the run-5 build.ninja closure (46 targets +
transitive deps) and a header scan resolved against the real -I roots of
the compile rules:

- 14133 tracked files removed (1.25 GB), incl. include/ArcGIS (1.03 GB),
  include/rti stubs (identical copies of the external RTI headers),
  out-of-scope Lts/Application, Lts/Viewer, Lts/Services/*, Lts/Tools
  generators, src/, tests/, specs/, translations/, external/
- kept: the 46 scope modules + their transitive service deps, codegen
  inputs (.xml, .grantlee), doxygen/ (configure_file at configure time),
  include/GeographicLib (libGeographicLib.so linked from the source tree),
  the 12 referenced include/ stub headers, pipeline files
  (new_docker_build_release2.sh, rpmbuild/, jenkins-ci-rme/, cmake/)
- 7 CMakeLists updated: drop add_subdirectory calls of the removed dirs
  (tests, translations, Lts/Plugins/ProjectDataManagement, qav, scripts,
  CommonUnitTestsPlaceholder, httq, LtsRestClient, LtsWebSocket,
  TopicEditorBase, ConnectDialog, StyleManager, Routing, DdsUnitTests,
  DdsUnitTestsPlaceholder, Light, Dark, Test, ExerciseManagement,
  ParticipantManagement, the 3 tools generators)

Result: 2157 tracked files (was 16290).

qt6-after/qt6-migrated-legatus/include/grantlee/grantlee_version.h

@@ -1,7 +0,0 @@
-#define GRANTLEE_VERSION_MAJOR 5
-#define GRANTLEE_VERSION_MINOR 3
-#define GRANTLEE_VERSION_PATCH 0
-#define GRANTLEE_VERSION_STRING "5.3.0"
-#define GRANTLEE_VERSION ((5<<16)|(3<<8)|(0))
-#define GRANTLEE_MAJOR_MINOR_VERSION_STRING "5.3"
-#define GRANTLEE_MIN_PLUGIN_VERSION 0