Fix warnings/errors on MSVC (#753)

* Fix warnings/errors on MSVC
1. update googletest to tag release-1.11.0 to make googletest and
   googlemock compile on MSVC2022.
2. set gtest_force_shared_crt to ON in test cmake project to make tests
   compile on MSVC.
3. add /wd4251 and /wd4275 to MSVC compile flags to ignore DLL related
   warnings for class exports.
4. fix some other warnings and errors while compiling on MSVC2022.

scripting/erm/ERMParser.h

@@ -256,7 +256,7 @@ namespace ERM
 	//script line
 	typedef boost::variant<TVExp, TERMline> TLine;
 
-	template <typename T> class ERM_grammar;
+	template <typename T> struct ERM_grammar;
 }
 
 struct LineInfo

scripting/lua/api/BonusSystem.h

@@ -12,7 +12,7 @@
 
 #include "../LuaWrapper.h"
 
-class Bonus;
+struct Bonus;
 class BonusList;
 class IBonusBearer;