Update skeleton and README to new assignment implementation: redesign of
thread pool, the use of generic lists.

Signed-off-by: Razvan Deaconescu <razvan.deaconescu@upb.ro>

Update formatting of source code and tests. Fix typos / inconsistencies
in `README.md`.

Signed-off-by: Razvan Deaconescu <razvan.deaconescu@upb.ro>

Add skeleton files in `src/`.
Add tests in `tests`/.
Add `README.md`.
Update `local.sh` and `.gitlab-ci.yml`.

Signed-off-by: Razvan Deaconescu <razvan.deaconescu@upb.ro>

These are setup and checker files for Operating Systems assignments.

Signed-off-by: Razvan Deaconescu <razvan.deaconescu@upb.ro>