Create Known Issues section in release notes

[simitt]

Create a dedicated section Known Issues in apm-server docs. The goal is that all known issues from a specific version are easily searchable and users can get a good overview before upgrading to a certain version.

The discussed approach is as follows:

• have one common asciidoc where known issues are collected
• per release note version, pull in the existing known issues from the common file

[colleenmcginnis]

👋 @simitt are there existing known issues documented elsewhere that I can pull from or should a create an empty page for now that the team can add to as needed?

Edit: I just see two in the changelog files: 8.5.asciidoc and 7.9.asciidoc.

[simitt]

An empty page to start with sounds good; I think we'll need to go through a couple of different sources to pull the Known Issues together.