Display number of new errors in a Release/Tag

We are introducing a first class Releases concept, which is great. We should extend this to also stats on how many errors were reported as new in this release, as well as how many were resolved.

On this page we can show simply the summary number, and clicking on that number will take you back to the issue list filtered by that release. https://gitlab.com/gitlab-org/gitlab-ce/issues/56045