Add missing content (GitLab acquisition blog post, etc.)
The content source is from July 2021, and some articles are missing.
The most important is the acquisition announcement where many URLs are incoming.
Boring solution: I copied an existing article file, and manually copied the text from the websites, added some URLs and formatting.
Additional things to consider: Some more blog posts in https://opstrace.com/blog but I don't think that they are needed now.
cc @kbychu