View, create and edit (tasks) tests & groups

backend/app/crud/tests.py

backend/app/routes/tests.py

backend/app/schemas/tests.py

frontend/src/lang/fr.json

frontend/src/lib/api/tests.ts

frontend/src/lib/components/studies/StudyForm.svelte

frontend/src/lib/components/tests/GroupForm.svelte

frontend/src/lib/components/tests/TestForm.svelte

frontend/src/lib/components/utils/Draggable.svelte

frontend/src/lib/types/testTaskQuestions.ts

frontend/src/routes/admin/tests/+page.svelte

frontend/src/routes/admin/tests/[id]/+page.server.ts

frontend/src/routes/admin/tests/[id]/+page.svelte

frontend/src/routes/admin/tests/[id]/+page.ts

frontend/src/routes/admin/tests/groups/+page.svelte

frontend/src/routes/admin/tests/groups/+page.ts

frontend/src/routes/admin/tests/groups/[id]/+page.server.ts

frontend/src/routes/admin/tests/groups/[id]/+page.svelte

frontend/src/routes/admin/tests/groups/[id]/+page.ts

frontend/src/routes/admin/tests/groups/new/+page.server.ts