Add a merge request template for merging software spotlights

With more and more MRs incoming, it would be handy to have a Merge Request template with a checklist for the software spotlights.

Things to be done for this issue:

• add a template
• update CONTRIBUTING

added Software Spotlight label

assigned to @christian.meessen

changed title from Add an issue template for merging software spotlights to Add an merge request template for merging software spotlights

mentioned in commit 587d284a

mentioned in merge request !493 (merged)

marked the checklist item update CONTRIBUTING as completed

marked the checklist item add a template as completed

changed title from Add an merge request template for merging software spotlights to Add a merge request template for merging software spotlights

closed with merge request !493 (merged)

mentioned in commit fd4ab763