Stop bundle/npm installing as root
Stop bundle/npm installing as root

Running NPM install as root was causing the pre-install hook to fail due
to the privilege drop. Additionally, the script wasn't actually in place
anyway compounding the sadness. Now we're switching to the docker user
for installing dependencies and copying the scripts directory into the
image first.

Change-Id: Ieaf38d9cd9947e7f809796e38340e10033ae1eb7
Reviewed-on: https://gerrit.instructure.com/101437
Tested-by: Jenkins
Product-Review: Caleb Guanzon <54fa1f30d451e4f3c341a8f3c47c9215fd0be9c6@instructure.com>
QA-Review: Caleb Guanzon <54fa1f30d451e4f3c341a8f3c47c9215fd0be9c6@instructure.com>
Reviewed-by: Brad Horrocks <7b5c5d1f2eba6c540b8e53f17d87a9bd7dbf604b@instructure.com>

sfu/canvas-lms,venturehive/canvas-lms,instructure/canvas-lms,venturehive/canvas-lms,SwinburneOnline/canvas-lms,venturehive/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,instructure/canvas-lms