remove installing of dependencies
remove installing of dependencies

dependencies will need to be installed prior to running
docker_dev_setup.sh. check for dependencies, if any are missing
notify user and kill script.

flag = none
fixes: DE-446

Test Plan:
- Jenkins passes
- running on mac and linux
 - with all dependencies
  - script sets up canvas docker
 - without all dependencies or older version of docker-compose
  - script exits with clear message about missing dependencies
  - after installing missing packages, rerun script
   - script runs successfully

Change-Id: I9b0aed276635ae1d9df177fcf3934865d970f90c
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/257368
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
QA-Review: Kyle Rosenbaum <08c6582752644f4eca90309d6d9805aeb3128ceb@instructure.com>
Product-Review: James Butters <4c5a489c9bb72d41f20b3b22aaf4c9b864e32f20@instructure.com>
Reviewed-by: Aaron Ogata <11ccf682c06d1508642f943a3962a1c3d00b8e44@instructure.com>

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