EStop button should display robot state

[IceSentry]

• Changes the text to "rearm" and change button color to yellow when the estop is activated on the robot
• Show unavailable and grey out the button when not connected and when no data has been published for more than X seconds.

The node is technically implemented on the robot, but it hasn't been tested for a long time. The react code is also probably not up to date either.

[IceSentry]

Technically, this node https://github.com/clubcapra/markhor/tree/master/markhor_estop should publish the status of the estop. From the UI perspective the code is already done to change the button text to rearm based on the status on that node. Unfortunately this hasn't been test in a long time. See this for the UI implementation

capra_web_ui/src/renderer/components/EStopButton.tsx

Line 24 in 8f9e84f

useRosSubscribe(topic, (message) => {