UI: Add Help -> Crash Reports submenu

Adds the ability to upload crash reports, making it easier for users to
give us crash data.  This should be considered a temporarily solution,
as automated crash reporting should be the ideal solution as soon as
time permits.

UI/obs-app.hpp

@@ -116,6 +116,8 @@ public:
 	const char *GetLastLog() const;
 	const char *GetCurrentLog() const;
 
+	const char *GetLastCrashLog() const;
+
 	std::string GetVersionString() const;
 	bool IsPortableMode();