Use Verdaccio local registry for E2E tests

[matejchalk]

• currently we use NPM workspaces to e2e test configs with plugin imports
  • requires running npm install after first package builds
• Nx supports Verdaccio for publishing project's to local registry
• @nx/plugin:e2e-project generator sets up local registry setup and teardown for E2E testing
  • it only supports Jest (and CJS because of require.resolve('nx')), but we should be able to replace it with Vitest using globalSetup option
• replace imports in e2e/cli-e2e/mocks/code-pushup.config.(mjs|js|cjs|ts)