Use OpenGL 3.3 core profile instead of compatibility profile

- Rename OpenGL to GLES3 in the source code per community feedback.
  - The renderer is still exposed as "OpenGL 3" to the user.
- Hide renderer selection dropdown until OpenGL support is more mature.
  - The renderer can still be changed in the Project Settings or using
    the `--rendering-driver opengl` command line argument.
- Remove commented out exporter code.
- Remove some OpenGL/DisplayServer-related debugging prints.

platform/android/os_android.cpp

@@ -262,14 +262,14 @@ Size2i OS_Android::get_display_size() const {
 }
 
 void OS_Android::set_context_is_16_bits(bool p_is_16) {
-#if defined(OPENGL_ENABLED)
+#if defined(GLES3_ENABLED)
 	//if (rasterizer)
 	//	rasterizer->set_force_16_bits_fbo(p_is_16);
 #endif
 }
 
 void OS_Android::set_opengl_extensions(const char *p_gl_extensions) {
-#if defined(OPENGL_ENABLED)
+#if defined(GLES3_ENABLED)
 	ERR_FAIL_COND(!p_gl_extensions);
 	gl_extensions = p_gl_extensions;
 #endif
@@ -321,7 +321,7 @@ OS_Android::OS_Android(GodotJavaWrapper *p_godot_java, GodotIOJavaWrapper *p_god
 
 	main_loop = nullptr;
 
-#if defined(OPENGL_ENABLED)
+#if defined(GLES3_ENABLED)
 	gl_extensions = nullptr;
 	use_gl2 = false;
 #endif