Add link sharing.

example.env

package-lock.json

package.json

src/lib/auditors/config.ts

src/lib/components/CopyClipboard.svelte

src/lib/components/ShareLinkModal.svelte

src/lib/components/test_cases/TestCaseView.svelte

src/lib/server/config.ts

src/lib/situations.ts

src/routes/__layout.svelte

src/routes/index.svelte

src/routes/simulations/[simulation].json.ts

src/routes/simulations/[simulation].svelte

src/routes/simulations/index.json.ts

svelte.config.js