Add ACTIVITY LED Support

[Ativerc]

I have not yet implemented the functionality of blinking the ACTIVITY LED connected to the device. I wanted to do this perfectly in the first go by implementing concurrency, but to implement concurrency, I have to read up on it a bit. So, instead of waiting to read up on concurrency, I will first do it without concurrency.

Reasons for using concurrency:

The ACTIVITY LED is supposed to blink once after each ping response received or ping timeout. In Normal mode with Internet connection, the ping is done once every 5 seconds. Upon Network or Internet failure, this increases to once every second.

Thus the ping interval in Normal Mode is 5 seconds and for Failure mode is 1 second.

Now, if implemented without concurrency and say the blink duration set to X milliseconds(ms), the ping interval during normal mode will increase to 5.x second and 1.x second.

This is what I want to avoid.

However, I will implement it without concurrency for now.

[Ativerc]

Activity LED has been enabled without concurrency since the past few days. Working on a few edge cases which causes the system to become unreliable.