add the "originals" volume to the staging deploy

[alishaevn]

refs #172

Present tense short summary (50 characters or less)

I need to test a bulkrax import using the server paths. on april 6 I added a csv and files to the "originals" mount on staging (seen below), but today that volume isn't there anymore. this change should make the volume permanent.

Changes proposed in this pull request:

• add an "originals" volume on staging

resources

• https://playbook-staging.notch8.com/en/learning-resources/kubernetes/krsync (step 2 under "prerequisites")

@samvera/hyku-code-reviewers