DeviceSettings: advanced_preferences: Add toggles for TCP Control Algorithm

This should work. I'm not sure as I can't test. This adds an entry in Galaxy Ace 2 settings to change the current TCP Control Algorithm. It needs https://github.com/TeamCanjica/Samsung_STE_Kernel/pull/2 as that enables the variety of algorithms to choose from. 

To test whether it works, after changing the algorithm in Galaxy Ace 2 settings, enter the following command in terminal:
busybox sysctl net.ipv4.tcp_available_congestion_control

The first algorithm that returns is the currently selected one.