Build a Sentry + hvac Docker image

Summary:
The hvac Python library can be used in sentry.conf.py
to fetch credentials from Vault.

Ref T1791.

Test Plan: Deployed on docker-002

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1791

Differential Revision: https://devcentral.nasqueron.org/D2901