Marge bot integration

[Vlad Zahorodnii]

Hi,

In kwin, we experience merge congestion issues where pending merge is 
aborted because another merge request has been merged in meanwhile, so 
you need to go back to the MR, rebase it and schedule a merge again. 
This is exhausting and frustrating developer experience.

Fortunately, this kind of issues can be solved by using 
https://github.com/smarkets/marge-bot. With marge bot, when all review 
comments have been addressed, you need to assign the MR to the marge-bot 
user. After that, it will try to merge the patch and if needed rebase 
and retry again. marge-bot is used by projects such as Mesa, pulse 
audio, various GNOME projects, etc.

I think that marge-bot would make merging patches in projects with high 
traffic such as plasma a lot easier. Thoughts?

Regards,
Vlad