E2Ev2: Split Fixtures

[RXminuS]

This PR restructures and modularizes the E2Ev2 fixture. The new structure aims to make the fixtures more manageable and easier to understand by separating the logic into different files:

1. mitmProxy.ts: Sets up a proxy to intercept and manipulate network requests during tests.
2. options.ts: Manages option schemas and validation for worker and test contexts.
3. polly.ts: Integrates the Polly library to record and replay HTTP interactions.
4. vscode.ts: Manages the setup and teardown of the VSCode server used in tests.
5. kitchensink.ts: Temporary placeholder fixture that holds all remaining fixture aspects.

These partial fixtures are then joined in index.ts

Test plan

CI