profile pic config: kill "avatar" copy

fixes CNVS-12070

test plan:
  * enable profiles and user avatars
  * open user settings
  * edit profile picture
  * verify that it doesn't say "avatar" anywhere

ticket requirements:
  * Select Avatar header text should say Select Profile Picture.
  * Select Image button should say Upload.
  * When the profile picture is saved to the profile pictures folder, the default filename should not be avatar. Change it to profile.jpg.
  * In the Upload a Picture tab, the select a photo link should say select a picture. Once the user has chosen a photo, the crop text should be updated so the button says Upload, not Select Image.
  * In the Take a Picture tab, the Take Snapshot button should say Take Picture.

Change-Id: I8e0ff9712faabb3e0a398332d84fa1981d1b4d2d
Reviewed-on: https://gerrit.instructure.com/32508
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Trevor deHaan <tdehaan@instructure.com>
Reviewed-by: Jon Willesen <jonw@instructure.com>
Product-Review: Braden Anderson <banderson@instructure.com>