Rename situation to testCase.

src/hooks.ts

src/lib/components/test_cases/TestCaseEdit.svelte

src/lib/components/test_cases/TestCaseView.svelte

src/lib/components/test_cases/TestCasesPane.svelte

src/lib/server/situations.ts

src/lib/session.ts

src/routes/__layout.svelte

src/routes/simulation.svelte