Provide togglable trend line on metrics

[auxesis]

@mkorourke wrote:

What is the feature?

Projected rate in X months on graphs

What is the business requirement for this feature?

• Capacity prediction and better capacity management
• Better ability to see capacity issues before they hit us

How does the feature work? (e.g. I go to the graphs and check a box and a magic line appears)

• Something along these lines, perhaps also a slider to specify the projection period. If a slider is difficult then the ability
  to select 6months, 12 months, 18 or 24months growth from a drop down graph type.
• Alerting on projection threshold would completed the solution.
• sample screenshot attached