[Refactor:System] Remove submitty_count from default

[dagemcn]

What is the current behavior?

Fixes Submitty Issue#11784 - This one of the companion PRs to Submitty PR#12609.

What is the new behavior?

submitty_count is longer installed in preparation for deprecation.

Other information?

This is a breaking change. Any autograding that uses the old submitty_count instead of submitty_count_ts will no longer work.

1. Follow the instructions on this page up to step 6 with the Dockerfile modified in this PR. (you may be able to reuse the one I used dagemcn/dockerimages:default-test adding it through docker UI)
2. After you have added the new docker image with the DockerUI, update the config of any gradeable with submitty_count with

"autograding_method": "docker",
"container_options": {
    "container_image": "IMAGE_NAME"
},

where IMAGE_NAME is the name of the image, for example, dagemcn/dockerimages:default-test if you reused mine.
3. Create a gradeable using submitty_count, (Tutorial examples 04, 06, and 07 all utilize submitty_count)
4. Test that submitty_count will not work in the config and that submitty_count_ts successfully runs
5. Also test that regular autograding works successfully on the image

Attached is a zip of a sample solution and gradeable config with both submitty_count and submitty_count_ts commands present for testing.
example.zip