Remove ZFBrowser & Update Tablet Browser#3109

The current tablet browser solution uses the third-party Unity plugin ZFBrowser, which is no longer maintained (and hasn’t been updated for 6+ years). It has a lot of bugs, memory leaks, and potential vulnerabilities. There are plenty of other options available (like Vuplex 3D WebView) that would be better options and could run things like HTML5 and WebGL without memory leaks.