SCons: Add methods.get_version_info() method returning a Dict

This makes it possible to retrieve all relevant versioning info used to
generate `core/version_generated.gen.h` in the buildsystem.

Notably it makes the custom logic parsing the `GODOT_VERSION_STATUS`
environment variable to override status easy to reuse.

(cherry picked from commit d432fe38a9)

SConstruct

@@ -619,7 +619,7 @@ if selected_platform in platform_list:
 
     env.module_list = modules_enabled
 
-    methods.update_version(env.module_version_string)
+    methods.generate_version_header(env.module_version_string)
 
     env["PROGSUFFIX"] = suffix + env.module_version_string + env["PROGSUFFIX"]
     env["OBJSUFFIX"] = suffix + env["OBJSUFFIX"]