Upgrade to Vue 3

[walterdeboer]

Current Behavior

Frontend now uses outdated Vue 2

Proposed Behavior

Move to Vue 3 after #445 is resolved:

• upgrage to Vue 3:
  • https://v3-migration.vuejs.org/
  • https://www.vuemastery.com/blog/vue-3-migration-build/
  • https://www.vuemastery.com/blog/migration/
• Upgrade BoostrapVue 2 -> 3 (not available yet: https://bootstrap-vue.org/vue3)
• upgrade to Bootstrap 5
• Upgrade to CoreUI 4.x
• Replace vue2-org-tree by https://www.npmjs.com/package/vue3-blocks-tree
• upgrade other dependencies

Checklist

• [X] I have read and understand the contributing guidelines
• [X] I have checked the existing issues for whether this enhancement was already requested

[sekwah41]

I will open a draft pr and start work on a new attempt at this. Originally I was considering moving to Vite though since the last time I looked vue has suggested switching to vite and moved the old methods to maintenance mode.

I did a little investigation before and the errors tend to be a lot more informative with vite though as it was switching the core tools over I decided against it as I didnt want to have to convince the wider community of a tool change.