[GitLab] Updated to 11.1

[Carlos Soriano <csoriano gnome org>]

What's important for us?

- Performance improvements

- Rewrite of the MR backend. Should be much smoother and allow to review bigger files.

- Changed MarkDown backend to CommonMark. Many of the issues we had before with the MarkDown are now fixed, the backend is the same as GitHub uses.

- File name filter on search

- Disable 3rd party offerings switch. No more Kubernetes ads :)

Some design changes

- MR design improvements

- Milestones page improvements

- Groups popover

WebIDE

- Manage MRs

- Some commit/stage improvements