vue-full-calendar is not the official Vue package of fullcalendar, is
only compatible with Vue 2.x, uses the outdated fullcalendar v3 library
and contains a bunch of huge dependencies like jQuery and moment.

The changes in this commit migrate the dashboard to fullcalendar v5 and
the official vue component. Apart from that there have been a few
refactors and fixes. These are:

* remove irrelevant stub event callbacks
* make view updates reactive instead of imperative
  (see removal of renderView method and introduction of renderWatcher)
* rename methods to better reflect their purpose
    resolve → enterConflictMode
    resolveEvent → resolveConflict
* emit events in modals instead of call to methods on this.$parent
* let → const where applicable to prevent accidental reassignments
* switch to for-of loops (from for-in) for better readability
* fix some typos

One other major change is that timeslot and collision data is no longer
mixed with event data for fullcalendar and is assigned to the
extendedProps property instead. As mentioned in fullcalendars
documentation on event parsing [1], any data that fullcalendar does not
handle on its own is moved into the extendedProps object with the
explicit recommendation to put them there right from the start. We
follow that recommendation.

closes #94

[1] https://fullcalendar.io/docs/event-parsing

fixes #87

Making imperative DOM API calls to apply CSS classes is
counter-productive when using a reactive frontend framework like Vue.
DOM attributes should instead be assigned based on reactive data.

fixes #117 and #118.

Notable changes:
 * Vue 2.6 to Vue 3 + compat migration.
 * Build system migration from vue-cli/webpack to Vite.
 * Application dependencies like bootstrap-vue, vue-router, vuex,
   or vue-toast-nofitication have been updated, if doing so was
   necessary or advisable for the Vue 3 migration.
 * Static file includes for the oidc-client in oidc_callback.html
   and oidc_callback_silentRenew.html have been removed in favor
   of automatic processing in the build system so that all assets
   are versioned and invalid cache hits are prevented.

Fixes #53 and #110.

moment is still needed as peer dependency but we should’t use it in our
own code anymore so we can remove it in the future.

We explicitly pass authorization for all requests and so no implicit
credentials need to be passed.

This reverts commit d37643bd.

This reverts commit 618bef34.

This reverts commit 4a37062d.

feat(nginx): deploy dashboard standalone

Closes #105

See merge request !12

Nginx in the Docker-container now ONLY deploys dashboard on
port 80. All configs related to other services will be moved to a
separate container. Certbot has been removed from the Dockerfile.

Fixes #105

This reverts commit 03470ca4.

Fix error code handling for scheduling API

Closes #93

See merge request !11

Allow API store consumers to use traditional flow-control

See merge request !10

Update toolchain and cleanup code

See merge request !9