chore: migrate from Parcel v1 to Vite

[eglitise]

The time has finally come. This PR ditches Parcel v1 and migrates to the very latest (!) version of Vite! 🎉
Other changes include:

• Simplifying the @import paths for the .less styling file (this didn't work in Parcel)
• Removing the additional HMR code in index.jsx (Vite supports this by default)
• Using an alias to solve the problem with handling web/Electron polyfill imports (probably also possible in Parcel, but likely not as straightforward, since there was no dedicated Parcel config file)
• Changing i18n locale paths depending on whether dev or production mode is used
• Skipping the browser build in Azure pipelines during publishing (this is not directly related to Vite)
• Updating the node scripts for consistency and ease of use
• Moving to vitest for unit and integration tests. E2E tests were left as-is, but I don't think they have ever worked anyway.

Some explicitly imported dependencies used with Parcel can now also be removed (e.g. postcss), but I am trying to keep this PR as small as possible, so that will come in a separate PR. It will also include the removal of mocha/chai and E2E tests being commented out, to be rebuilt in the future.

Basic functionality was tested on both macOS and Windows for:

• Browser dev build
• Browser production build
• Electron dev build
• Electron production build
• Electron packaged app

One unexpected benefit from this migration is that the app seems to open notably faster as well!

Closes #1453.

[eglitise]

Hmm that's odd, I had the tests run just fine previously...

[jlipps]

amazing work!

[KazuCocoa]

lg overall, I'll do some testing on my local as well tomorrow.

[KazuCocoa]

lg overall. Ran them on my local as well. Had the same comments for the path related (to use join) which is already addressed, although others look good for me.