Slack integration feedback

A few requests for the Slack integration:

• The buttons in ALL CAPS looks really jarring

• It was hard to find the link to view the run details. Since the info presentation for the Show changes buttons isn’t very useful, I’d rather just have a clear link to view the run details in a browser

• It would be nice if there was a compact/one-line version of the message with a short summary and link to the run that we could choose to use instead

• The per-channel setup in the Spacelift UI is pretty difficult since you have to grab the actual Slack channel ID, not just the channel name