Backport "Make RabbitMQ a regular Erlang/OTP application" to RabbitMQ 3.8.x

[dumbbell]

This issue allows us to track the progress of the backport of #2180 to RabbitMQ 3.8.x.

[gerhard]

Looking forward to this getting into 3.8 🎉

[dumbbell]

The backport is done and tested successfully locally. I verified the diff between those backport branches and master branches to make sure I didn't forget a commit.

The only difference around those changes is related to the product info. Some commits were already backported to v3.8.x, but not everything. I'm not adding the missing bits now because it is out-of-scope.

I just fixed the pull request to the broker (#2282): it was based on master, not v3.8.x. The patch doesn change and I restarted the test on Travis.

[lukebakken]

Some commits were already backported to v3.8.x, but not everything. I'm not adding the missing bits now because it is out-of-scope.

How can we keep track of what is missing?

[dumbbell]

How can we keep track of what is missing?

They are still to be QA'd in master and were backported prematurely. So once everything is finished in master, I will take care of backporting everything at once.

[lukebakken]

Thanks @dumbbell !

[michaelklishin]

Are there more backports pending?

[dumbbell]

Yes, at least #2277 which is not ready yet.

[dumbbell]

#2277 was merged to master and backported to 3.8.x.