Integrate Support for Live HRL into HRL Plugin

[Evan Palmer]

This issue is directly linked to the following Swarm Planner Issue: https://github.com/unl-nimbus-lab/SwarmPlanner/issues/74

Describe the solution you'd like
As of now the HRL manager has a single button that toggles between:
"start path execution" (and sends "0" over the debug int message) and
"stop path execution" (and sends "1" over the debug int message).

In order to support "Live HRL" would like this to be 3 buttons like
"Deploy Start" (and sends "0" over the debug int message)
"Preplanned Point" (and sends "1" over the debug int message)
"Live HRL" (and sends "2" over the debug int message)

Additional context
Adding a new flight mode to the agents and need to be able to set it from the GCS