Decouple FreeRTOS from everything

[kammce]

Feature Request

A hard coupling to FreeRTOS will make adding additional RTOSes difficult to integrate in the future. Decoupling now and adding some sort of installer for FreeRTOS at runtime would be the better approach if it is possible. This issue corresponds to #427.

Detailed Description

Preferred execution would be something like the following.

#include "platform/operating_system/freertos.hpp"

int main()
{
  sjsu::InstallFreeRTOS();
  // ...
}