Vue 3 Migration

https://github.com/ecamp/ecamp3/tree/vue3

- [x] DialogFormBase
- [x] fix eslint.config.mjs (flat config for vue3) @BacLuc
- [x] fix Vee-validate @usu
- [x] set locale for validation messages
- [x] * for required fields (style not working) @manuelmeister
- [x] cross validation (vid / veeId)
- [x] ApiWrapper: check for validation errors and don't save to API in case of errors
- [x] ETextField (partial implementation for vee-validate already existing; also check changes on devel on ETextField) @usu
- [ ] Check reactivity in the other ApiInput and EInput components
- [x] Picasso
- [x] event display @BacLuc
- [x] drag + drop @BacLuc
- [x] resize @BacLuc
- [x] create @BacLuc worked once, now broken again. (Validation ~~always~~ too often fails for date)
- [x] dialogues
- [x] Activity create: as soon as you touch the datepicker or the timepicker, the validation will always fail.
- [x] Activity edit: as soon as you touch the datepicker or the timepicker, the validation will always fail.
- [x] As soon as you add a second schedule entry, the validation will always fail
- [x] changes in dayresponsibles are not sent to the backend
- [x] picasso sidebar @BacLuc -> removed for now, we have enough on our plate: https://github.com/ecamp/ecamp3/issues/8492
- [x] auth.js / loadUser infinite loop @BacLuc
- [x] Store setLanguage (aktuell auskommentiert in Profile.vue, etc.) @BacLuc
- [x] fix Sentry configuration in main.js
- [x] fix loading of unhead in main.js
- [x] source maps
- [x] Local Dev Performance
- [x] Activity Filter Reactivity @carlobeltrame
- [x] Prod build
- [x] materiallist
- [x] Overview: it's not possible to change the materiallist temporary fixed with https://github.com/ecamp/ecamp3/commit/2c7e22ed61ac0914911dc793a7569b493959344e
- [x] materialtable (in schedule entry) @simfeld
- [x] print configurator
- [x] first sweep of fixes done with AI. We will need to look if we need all changes.
- [x] story @simfeld
- [x] checklist admin @pmattmann
- [x] freezes when there are too many items. @BacLuc Seems to have been a caching issue in my setup. (Console reported errors in the CategoryTemplate...?). Can someone check if checklist admin works with a lot of items?
Improved it a little be delaying the activation of the draggable thingy which crashes the browser.
- [x] checklist @pmattmann
- [x] activity
- [x] layout edit
- [ ] Category edit
- [ ] it crashes when there are already elements. This only happens in the prod build
- [x] drag-and-drop for progress labels
- [ ] Alle draggable @manuelmeister
- [ ] Fix vite reloading the whole page when new components are encountered during routing
- [x] replace `$listeners` uses @carlobeltrame
- [x] Collaborators.vue
- [ ] Register page
- [x] fix validation @usu
- [ ] fix PasswordStrengthChecker
- [ ] Form Components
- [x] ETextField/ApiTextField: Done (but consider refactor back to OptionsApi)
- [x] ECheckbox/ApiCheckbox
- [x] ESwitch/ApiSwitch
- [x] ESelect
- [x] ERichtext/ApiRichText @simfeld
- [x] ENumberField/ApiNumberField
- [ ] open issue: text input is properly parsed but still visible to user
- [x] DatePicker
- [x] manual date entry still cumbersome (invalid date object)
- [x] vee-validate not yet implemented
- [x] TimePicker
- [ ] vee-validate not yet implemented
- [x] ColorPicker
- [ ] check all usage of @input and emit('input') and verify, if it should be changed to 'update:modelValue'
- [ ] Login: test(at)example.com
- [ ] Create Camp
- [x] Create camp without prototype
- [x] Create camp with prototype
- [x] Validation in camp create dialog
- [x] Make it look less ugly (maybe for @manuelmeister )
- [x] Fix Dialog openState / v-model handling @carlobeltrame
- [ ] personal invitations @pmattmann
- [x] Profile
- [x] the language dropdown shows German many times (and nothing else)

# First run through by @BacLuc

Good news: the Meta part of a camp works (create, invite, create activities, material list, print camp).
Excel download of material lists does not work yet and saving Textareas (so the program parts).

## progresslabel
- [x] progressLabel patch does not work
- [x] reordering does not work

## category @carlobeltrame

- [x] edit completely broken
- [x] create: you need to choose color, this is not very visible
- [x] edit: layout and content are switched
- [x] pasting category does not work

## checklist

- [x] create does not work

## materialist admin

- [x] change name does not work
- [x] delete material list does not work (no id in url)

## print

- [x] layout1: picasso cannot be printed
- [x] detailprogramm cannot be printed
- [x] Selects in the printconfig don't work

## materiallist

- [x] excel download does not work
- [ ] validation of form happens even when not dirty

## Picasso

- [x] Scheduleentry form must look better
- [x] Times in scheduleentryform must be prefilled

## Activity

- [x] LA Thematic area select does not work
- [x] SingleText ContentTypes do not work

## Invitation
(When you accept an invitation per email)

- [ ] The buttons look all the same

## Profile

- [x] Current email is not displayed
- [x] change email does not work

## Reset password

- [x] validation is broken

## set password after reset

- [x] cannot submit form