Add MR status indication

[colens3]

Add additional indication on the MR in case:

• MR is commented
• MR is approved

This can be done simply by changing the icon (add some small differences to the icon like green, yellow dots) or if there is some better idea make a suggestion

[eleonnora]

Maybe to also have different icons for MRs:

• with all resolved comments
• with at least one unresolved comment