feat: implement module mocking in browser mode

[sheremet-va]

Description

This PR implements vi.mock API running in the browser.

Fixes #3046
Fixes #4097
Fixes #3138

The only limitation is we don't support automocking modules that have export * inside because we cannot statically analyze all exported names without transforming imported module.

// automocks a module
vi.mock(import('./some-module.js'))

// aliases to ./src/__mocks__/some-module.js
vi.mock(import('./src/some-module.js'))

// exposes exports through a factory
vi.mock(import('./src/some-module.js'), () => {
  return { namedExport: true }
})

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