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.

For vue-devtools see https://github.com/vuejs/vue-devtools

we don't need to show the method name as it will only
always show the es6 node core module of node an not
the actual method in our vue application.

as vue-resource is retired from official recommendation status
we switch to axios, which is better maintained and supports a
similar API.

for more background see:
https://medium.com/the-vue-point/retiring-vue-resource-871a82880af4