Revise global recruiter posting

@brittanyr @AshleyS @ernstvn Please review the changes made to the Recruiter posting. NOTE: the formatting may need some assistance. Let me know if you like the intro piece about GitLab. I would like to use this or something like it on all postings that we will send to outside job boards. Appreciate your feedback. If / When all is good, I'll assign to Ernst to merge. Thx very much!