doc: add documentation

- add documentation for CKGlobals, VxMath (partly)
- Fix build issue in CKDefines, CKGlobals, VxMath.
- Bring libcmo exception in CKGlobals and VxMath for some illegal input.

LibCmo/CK2/CKDefines.hpp

@@ -50,7 +50,7 @@ namespace LibCmo::CK2 {
 	/**
 	 * @brief The identifier of Virtools file.
 	*/
-	constexpr const CKCHAR CKNEMOFI[] = "Nemo Fi";
+	constexpr const CKCHAR CKNEMOFI[] = u8"Nemo Fi";
 	/**
 	 * @brief Current Version of CK Engine (Day/Month/Year)
 	*/