build: Setup test apps for upcoming snapshot tests

[nicholas-codecov]

Description

This PR adds in new test apps for the upcoming integration/snapshot tests that we will be introducing for a full e2e test experience for the three bundler plugins. As well as a few small tweaks all around for package.json, eslint, tsconfig, etc.

Notable Changes

• Create rollup, vite, and webpack test apps for upcoming snapshot tests
• Few tweaks to package.json files all around

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (0ba0d59) 86.06% compared to head (31b10e9) 86.06%.

Additional details and impacted files

Components	Coverage Δ
Plugin core	96.39% <ø> (ø)
Rollup plugin	7.14% <ø> (ø)
Vite plugin	7.14% <ø> (ø)
Webpack plugin	9.52% <ø> (ø)

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[AbhiPrasad]

Can we make sure the test apps are importing an npm dependency of some kind? I think it's useful to check what that will look like in snapshots.

We can also just make new test-apps for those scenarios