[zig] Add run examples using zig and emscripten for web

[maiconpintoabreu]

This PR is to allow: zig build -Dtarget=wasm32-emscripten textures_sprite_anim

Changes:

• if target.result.os.tag == .emscripten Steps are create as:
  • exe_lib - new
  • raylib - reused
  • ^ dependOn
  • emcc_command - new
  • ^ dependOn
  • run_step - new create by method emscriptenRunStep
• Add const module_resources = b.pathJoin(&.{ module_subpath, "resources@resources" }); to be able to map resources folder for the examples.
• Add run_step.addArg("--no_browser"); to run without running a browser so the user can point to the example manually.
• Skipping rlgl_standalone and raylib_opengl_interop examples for now.

Result:

Now you can compile examples like:

• zig build -Dtarget=wasm32-emscripten examples - it compiles all examples (except rlgl_standalone and raylib_opengl_interop for now)
• zig build -Dtarget=wasm32-emscripten core - it compiles all examples for the especified module.
• zig build -Dtarget=wasm32-emscripten textures_sprite_anim - it compiles a expecific example and serves it at default port 6931.

This PR has no impact on any binding as there is no change in method compileRaylib.

[raysan5]

@maiconpintoabreu thanks for the update!