Disable all 3D nodes, physics, and resources when compiling without 3D

[aaronfranke]

This PR disables all 3D nodes and resources, and ensures that some key files like World3D are not included anywhere, when compiling with 3D disabled. A summary of some of the changes:

• World3D is now not included at all when 3D is disabled, so I removed the 3D disabled checks from that file.
• PhysicsServer3D is not compiled when 3D is disabled.
• PackedScene no longer includes Node3D when 3D is disabled.
• Mesh no longer includes 3D physics shape generation methods when 3D is disabled.
• NavigationMeshSourceGeometryData3D was including VisualInstance3D, but it only needed Mesh. I changed this to including only Mesh.
• The above point broke NavigationServer3D and GodotNavigationServer3D since those need Node (but not Node3D), so I added a Node include for each of those.
• ShaderGlobalsOverride included Node3D, but it only needs the tree notifications, so I switched it to Node.
• RenderingLightCuller included Camera3D, but it does not need it, it only needs the core/math files.

Overall these changes are surprisingly clean, the last 4 bullets are just good fixes for including what you use. The big messy change is in the servers folder, with all the env.add_source_files lines in the SCsub file. I am of the opinion that we should move the server files into the server folders (like move PhysicsServer3D into the servers/physics_3d folder). But that should likely be a separate PR (maybe as a prerequisite to this one? or we can merge this first).

[akien-mga]

Changes look good to me.

Somewhat surprisingly though, this seems to make a disable_3d optimized build bigger than it was before.
Here's what I get with a local test with GCC 13.2.1:

-rwxr-xr-x. 1 akien akien  55515328 Mar 11 10:55 godot.linuxbsd.template_release.x86_64.disable3d
-rwxr-xr-x. 1 akien akien  55675040 Mar 11 11:15 godot.linuxbsd.template_release.x86_64.disable3d_pr89381
-rwxr-xr-x. 1 akien akien  64015424 Mar 11 11:00 godot.linuxbsd.template_release.x86_64.vanilla

Building with scons production=yes target=template_release disable_3d=yes scu_build=yes.

Not a big difference though, 156 KiB / 0.3% increase. But that's still a bit surprising when excluding more stuff.
And especially some analysis with bloaty had shown that PhysicsServer3D among other things was fairly big in a minimal build:

   0.5%  84.9Ki   0.5%  85.0Ki    servers/physics_server_3d.cpp

---

I tried without scu_build=yes as this may impact how well the linker removes unused code. The difference is smaller then, though still a tiny increase with this PR:

-rwxr-xr-x. 1 akien akien 55802016 Mar 11 11:53 godot.linuxbsd.template_release.x86_64.disable3d
-rwxr-xr-x. 1 akien akien 55818400 Mar 11 11:50 godot.linuxbsd.template_release.x86_64.disable3d_pr89381

Exactly 16 KiB increase, which is just 0.03%. So not very significant.

So overall this just seems not to have much impact on the binary size as is, which is a bit puzzling.

---

Tested on a super minimal build, no size difference:

-rwxr-xr-x. 1 akien akien 15576888 Mar 11 12:01 godot.linuxbsd.template_release.x86_64.master
-rwxr-xr-x. 1 akien akien 15576888 Mar 11 12:05 godot.linuxbsd.template_release.x86_64.pr89381

Built with

scons target=template_release production=yes disable_3d=yes disable_advanced_gui=yes optimize=size deprecated=no minizip=no modules_enabled_by_default=no module_gdscript_enabled=yes vulkan=no wayland=no build_profile=../blank.build

where blank.build is this build profile: blank.build.txt

[akien-mga]

Tested a minimal build with debug symbols to run bloaty on:

scons target=template_release production=yes disable_3d=yes disable_advanced_gui=yes optimize=size deprecated=no minizip=no modules_enabled_by_default=no module_gdscript_enabled=yes vulkan=no wayland=no build_profile=../blank.build lto=none debug_symbols=yes separate_debug_symbols=yes

Without LTO (needed to have usable debug symbols), I do get a more significant size difference. So LTO seems to do a good job at removing unneeded 3D code even without this PR.

-rwxr-xr-x. 1 akien akien  19742192 Mar 11 12:29 godot.linuxbsd.template_release.x86_64.master
-rwxr-xr-x. 1 akien akien 267118528 Mar 11 12:29 godot.linuxbsd.template_release.x86_64.master.debugsymbols
-rwxr-xr-x. 1 akien akien  19590640 Mar 11 12:25 godot.linuxbsd.template_release.x86_64.pr89381
-rwxr-xr-x. 1 akien akien 264093200 Mar 11 12:25 godot.linuxbsd.template_release.x86_64.pr89381.debugsymbols

148 KiB removed, i.e. 0.75%.

master build:

$ bloaty bin/godot.linuxbsd.template_release.x86_64.master -d compileunits -n 0 --debug-file bin/godot.linuxbsd.template_release.x86_64.master.debugsymbols | grep 3d   0.4%  84.9Ki   0.4%  85.0Ki    servers/physics_server_3d.cpp
   0.2%  42.7Ki   0.2%  42.7Ki    servers/navigation_server_3d.cpp
   0.1%  17.2Ki   0.1%  17.2Ki    core/math/geometry_3d.cpp
   0.1%  9.72Ki   0.0%  9.74Ki    scene/resources/3d/concave_polygon_shape_3d.cpp
   0.0%  8.47Ki   0.0%  8.47Ki    servers/navigation/navigation_path_query_result_3d.cpp
   0.0%  6.16Ki   0.0%  6.16Ki    scene/resources/3d/shape_3d.cpp
   0.0%  6.16Ki   0.0%  6.16Ki    core/math/transform_3d.cpp
   0.0%  4.69Ki   0.0%  4.71Ki    scene/resources/3d/convex_polygon_shape_3d.cpp

This PR:

$ bloaty bin/godot.linuxbsd.template_release.x86_64.pr89381 -d compileunits -n 0 --debug-file bin/godot.linuxbsd.template_release.x86_64.pr89381.debugsymbols | grep 3d
   0.2%  42.7Ki   0.2%  42.7Ki    servers/navigation_server_3d.cpp
   0.1%  17.5Ki   0.1%  17.5Ki    core/math/geometry_3d.cpp
   0.0%  9.12Ki   0.0%  9.12Ki    servers/navigation/navigation_path_query_result_3d.cpp
   0.0%  6.16Ki   0.0%  6.16Ki    core/math/transform_3d.cpp

Full bloaty compileunits output for both builds:
bloaty_minimal_master.txt
bloaty_minimal_pr89381.txt

[AThousandShips]

Confirmed building and testing works (i.e. does not introduce any regressions with debug templates and running tests)

[akien-mga]

Thanks!