Migrate all React code to Vue

[provokateurin]

How to use GitHub

• Please use the 👍 reaction to show that you are interested into the same feature.
• Please don't comment if you have no relevant information to add. It's just extra noise for everyone subscribed to this issue.
• Subscribe to receive notifications on status change and new comments.

Is your feature request related to a problem? Please describe.
Some parts of the app are still written in React which makes it harder to maintain and keep in line with the rest of Nextcloud

Describe the solution you'd like
Rewrite all React parts to become Vue.
Probably can be done incrementally, since the app already uses some Vue.
At the end remove all React dependencies and configuration.

[provokateurin]

470 src/settings/App.tsx
110 src/settings/QuotaSelect.tsx
33 src/settings/index.tsx
46 src/settings/SubmitInput.tsx
174 src/settings/FolderGroups.tsx
20 src/settings/SortArrow.tsx
96 src/settings/SubAdminGroupSelect.tsx
97 src/settings/AdminGroupSelect.tsx

Lines of React

[provokateurin]

One major thing to improve is error handling as currently any failing API request doesn't give any feedback to the user.