Feature: Post card comments for status updates.

[PiDelport]

(Idea lifted from discussion here.)

It would be nice if the plugin supported posting certain significant Sentry issue updates / state changes as comments on the issue's card.

Several types of notification are conceivable, but the two most compelling ones that i can think of are:

• Event trigger thresholds: "Issue reached 50 event triggers."
• Issue resolution: "So-and-so marked this as resolved." / "Issue was reopened."

For event triggers, eo prevent unexpected event floods from turning into comment floods, the reporting thresholds should probably be based on some non-linear scale: reporting on powers of 10 or 2 comes immediately to mind.