Android: Add usage statistics to android.

Added an option in General config to enable/disable usage statistics. Added a popup on first open if
the user would like to engage in reporting. Clicking cancel or out of the box opts out. Only
clicking 'Ok' will enable reporting. Also added a new android specific values to report.

Source/Core/Common/AndroidAnalytics.cpp

@@ -0,0 +1,27 @@
+// Copyright 2018 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include <functional>
+#include <string>
+
+#include "Common/AndroidAnalytics.h"
+
+namespace Common
+{
+std::function<void(std::string, std::string)> s_android_send_report;
+void AndroidSetReportHandler(std::function<void(std::string, std::string)> func)
+{
+  s_android_send_report = std::move(func);
+}
+AndroidAnalyticsBackend::AndroidAnalyticsBackend(std::string passed_endpoint)
+    : m_endpoint{std::move(passed_endpoint)}
+{
+}
+AndroidAnalyticsBackend::~AndroidAnalyticsBackend() = default;
+
+void AndroidAnalyticsBackend::Send(std::string report)
+{
+  s_android_send_report(m_endpoint, report);
+}
+}  // namespace Common