Improve startup error handling on MacOS

I installed the latest MH build on top of a much older one on my Mac and while the menu bar icon shows up, the admin console didn't launch automatically and when manually browsing it is unable to connect to port 8091.

This improvement is not about fixing whatever issue is preventing it from starting up (I understand the possibility of breaking changes between unsupported builds) but rather about improving the handling and visibility of when this occurs so that the user can identify and potentially resolve.

Some thoughts:

• When launching the Couchbase Server application, if it can't fully start up, it should shut down and provide some error back to the user
• If the application is able to start but not connect to itself on one or more ports, there should be a clear message in the menu bar icon
• The menu bar icon should include a way of quickly getting to the logs directory
• The menu bar icon could potentially allow for directly taking and uploading a cbcollect
• Other ideas?