Port dav calendar settings page to Vue.js

- Drop reliance on deprecated global jQuery object.
- Allow testing user interactions.
- Use newer technology stack.

---

Test user interactions with the groupware dav settings

Add infrastructure to test Vue components:

- Use recommended libraries:

    - https://vuejs.org/v2/guide/testing.html#Recommendations
    - Use jest-dom for robust assertions on the DOM state
    - Use user-event to be more representative of user actions

- Code is transpiled by Jest, with the help of vue-jest.

Ignore test files for no-unpublished-import. Prevent ESLint from
flagging:

```
/home/runner/work/server/server/apps/dav/src/views/CalDavSettings.spec.js
Error:   1:24  error  "@testing-library/vue" is not published         node/no-unpublished-import
Error:   2:23  error  "@testing-library/user-event" is not published  node/no-unpublished-import
```

Signed-off-by: François Freitag <mail@franek.fr>

1 files changed, 0 insertions, 1 deletions

diff --git a/babel.config.js b/babel.config.js
index c48171c8385..b801d768f03 100644
--- a/babel.config.js
+++ b/babel.config.js
@@ -7,7 +7,6 @@ module.exports = {
 		[
 			'@babel/preset-env',
 			{
-				modules: false,
 				useBuiltIns: false,
 			},
 		],