Blog post to celebrate wider community contribution from 2019 plus FOSDEM update

Why is this change being made?

This is a blog post to recap wider community contribution from 2019 and raise awareness on GitLab's FOSDEM participation.

Does this MR meet the acceptance criteria?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what

Closes #2019 (closed)