Integrate with notification providers (slack, teams ...)to reflect package install status/transitions

**Describe the problem/challenge you have**

These days messaging platforms has enabled pushing notification and customers can benefit by integrating with such platforms with kapp controller to receive the package status notifications.

Flux and many other open-source controllers provide such integrations.

**Describe the solution you'd like**

A similar notification for kapp controller would be good

**Anything else you would like to add:**
[Additional information that will assist in solving the issue.]

---
Vote on this request

This is an invitation to the community to vote on issues, to help us prioritize our backlog. Use the "smiley face" up to the right of this comment to vote.

👍 "I would like to see this addressed as soon as possible"
👎 "There are other more important things to focus on right now"

We are also happy to receive and review Pull Requests if you want to help working on this issue.