Revisit Creating an Actionable Sensor Example

[nperree-dstl]

I would like to revisit this example at some point to add some diagrams and improve the explanation. I am happy that it can be included as it is for the Sensor Management PR but it could be improved. NB: Some changes have been made since Jordi's review but I think it can be improved further.

"Overall I don't think this example is very clear. Too many words, too few diagrams. Needs to describe what an actionable sensor is in general, then give the simplest example.

Suggestion based on the fact that I recall the notebook with sectors drawn. 1. Create a sensor with a sector pointing North. 2. Draw it. 3. Action a 45 degree turn E. 3. Draw it. 4. Action a 90 degree turn W. 5. Draw it."

Originally posted by @jmbarr in https://github.com/dstl/Stone-Soup/pull/503#discussion_r764393850