add Setting to defer js bundles
add Setting to defer js bundles

so if we have a bundle or bundles that fail due to DOM-ready
race conditions exacerbated by Chrome 96, we can defer them
without a deploy while we fix the code

test plan:
 - Setting.set('deferred_js_bundles', 'foo,bar') will cause
   js_bundles `foo` and `bar` to be deferred
 - Setting.set('deferred_js_bundles', '*') will cause all
   js_bundles to be deferred
 - Setting.set('deferred_js_bundles', '*,!foo') will cause
   all js_bundles except for `foo` to be deferred

refs FOO-2597

Change-Id: Ie976608a869e576c9eb2e2da0bf89b73cbe68b4a
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/281060
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: Charley Kline <05950d7e90ba5e3da323378368c22b3ffaaf6647@instructure.com>
Product-Review: Charley Kline <05950d7e90ba5e3da323378368c22b3ffaaf6647@instructure.com>
QA-Review: Charley Kline <05950d7e90ba5e3da323378368c22b3ffaaf6647@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms