chore: update rockcraft project, add sanity test, and tox.ini file

[DnPlas]

This commit updates the rockcraft project to match the new requirements from the latest rockcraft version. It also refactors the security requirement to match the latest format in other rock repositories. Bash is now removed from the image as it is not required and not recommended in production environments, and the build dependency on apt is also removed as it was not used at all. Adding sanity tests in this rock's repository and its corresponding tox file.

Fixes #71

Testing instructions

Prerequisites:

• skopeo
• docker

1. Build the rock rockcraft pack -v
2. Save the rock as an OCI image in docker's local registry skopeo --insecure-policy copy oci-archive:kubeflow-central-dashboard_1.7_amd64.rock docker-daemon:cdash:0.1
3. Run a container with the image and replace the entrypoint with a shell docker run --rm -ti --entrypoint=/bin/sh cdash:0.1
4. Ensure that:

• The /app directory exists
• The permissions of the /app directory are drwxr-xr-x 11 _daemon_ _daemon_ 4.0K Feb 4 00:08 app
• You can run the command /usr/bin/npm start --prefix /app and it outputs the following message:

  Using Profiles service at http://localhost:8081/kfam
  Server listening on port http://localhost:8082 (in development mode)

[DnPlas]

The CI of this PR is currently failing because of https://github.com/canonical/charmed-kubeflow-workflows/pull/44. We must re-run everything once that gets merged.