Contribution kananen

[Kekananen]

Adding in Kathryn Kananen's information as a collaborator.

• Edit of the CONTRIBUTORS.yaml to have individual information
• Addition of 900px x 900px headshot in AVATARS

[meren]

The image is not 900x900 but 652×900 pixels :)

This will cause geometric issues downstream :p

[Kekananen]

I'll submit another PR with the corrected size. Apologies. I must have converted the file size incorrectly!