test(api): add integration tests for external api urls

[halfwhole]

Problem

We'd like to add integration tests for our external API URLs

Solution

Add integration tests for our external API to create, get, and update URLs at the /api/v1/urls endpoint.

• The strange ;( ... ) syntax in e.g. ;({ email, apiKey } = await createIntegrationTestUser()) was enforced by prettier, see this comment in their docs
• There's some duplication in logic for creating the API key, which seems unavoidable because the test environment is set up differently from the server
• inb4: I hope GitGuardian doesn't complain loudly about the API_KEY_SALT variable, it's used in local dev only surpisingly it looks like we're in the clear!

[thanhdatle]

LGTM