[keyserver] Delete deploy.sh

Summary: See @ashoat's comment on D4477. This diff removes deploy.sh since we don't use it anymore and instead use Docker in production.

Test Plan: N/A

Reviewers: ashoat, atul

Reviewed By: ashoat, atul

Subscribers: palys-swm, Adrian, ashoat

Differential Revision: https://phab.comm.dev/D4484