Adjust CoS hiring section to match GitLab styleguides

Why is this change being made?

1. Updating my own title since I got promoted last year
2. Employee is a mis-used term Communication#top-misused-terms, point 6.(also updating correct numbering given that I joined the company at its creation after Sid).

Employees => team members, since we have team members who are contractors

1. Convert bullets to numbered list Communication#writing-style-guidliness, point 12

If you have multiple points in a comment or email, please number them. Numbered lists are easier to reference during a discussion over bulleted lists.

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