Results: Implement namespaced, type-safe results.

Because I was working on multiple things at once, this commit also:
- Adds wrappers for/linker flags to wrap CXX exceptions to make them
  abort. This saves ~0x8000 of memory in every system module.
- Broadly replaces lines of the pattern if (cond) { return ResultX; }
  with R_UNLESS(!cond, ResultX());.
- Reworks the R_TRY_CATCH macros (and the result macros in general).

stratosphere/ams_mitm/source/fs_mitm/fs_istorage.hpp

@@ -102,7 +102,7 @@ class IROStorage : public IStorage {
             return ResultFsUnsupportedOperation;
         };
         virtual Result Flush() final {
-            return ResultSuccess;
+            return ResultSuccess();
         };
         virtual Result SetSize(u64 size) final {
             (void)(size);