set vault agent uid/gid to prometheus uid/gid to allow token access

General MR

Summary

sets vault agent uid/gid to prometheus uid/gid to allow token access

with these changes:

$ ls -la /vault/secrets/token 
-rw-r-----. 1 1000 2000 95 Jan  7 19:30 /vault/secrets/token

Relevant logs/screenshots

Shows prometheus working without any user intervention to vault or prometheus pods.

Linked Issue

Closes big-bang/product/packages/vault#126 (closed)

Upgrade Notices

N/A