> Issue tracker
There are bug trackers that have more features compared to Github/Gitlab.
> Merge requests that are easy to analyze
You can get that through pure git by using git format-patch and git send-email
> Ability to put comments during a code review on specific lines of code and discuss it from there
You can get that by replying inline to the email containing the patch (much like I'm doing here when replying to a certain part of your comment).
> Embedded wiki for a project
That could be maintained in the docs directory of the project
> Managing different access rights to different repos
Given that the project maintainer(s) maintain access to their repos, they could just as well handle the access rights without having to rely on Github/Gitlab.