Take over the Mylyn project page from predecessors

[mjmeijer]

We should manage this page as well
https://www.eclipse.org/mylyn/

[wimjongman]

Maarten, maybe you can take this? Please ask the webmasters on GitLab helpdesk to port the website to GitHub?

[wimjongman]

Maarten any update?

[BeckerFrank]

@mjmeijer, @wimjongman: It looks like the new location for the source is here but my first change (eclipse-mylyn/mylyn-website#2) shows not up in https://www.eclipse.org/mylyn/.

What is here the missing part?