feat(ui): new dynamic agenda view

[NGPixel]

Reworking of the agenda page into a fully dynamic Vue.js page.

Goals

• Modernize the UI / Improve ease of use
• Reduce page load time by making the filtering and other heavy operations by the client
• Use a modern client framework (Vue 3)
• Use Vite (instead of Parcel) for views using Vue 3 + Django-Vite integration

Instructions

To try in dev mode, you need to run yarn dev in a separate process, then start the server as usual. Unlike Parcel (where assets are written to disk and then read by Django), assets are generated on the fly and are proxied by Django to the Vite process listening on port 3000.

Remaining work / Known bugs

• Mobile view is buggy / missing panels
• Update URL to match current selection
• Write tests