chore: fix all linter warnings

[jaylinski]

Fixes all linter warnings:

> [email protected] lint
> eslint --ext .js,.vue src tests

/nextcloud-app-tasks/src/components/AppNavigation/Colorpicker.vue
  95:15  warning  Custom event name 'color-selected' must be camelCase  vue/custom-event-name-casing

/nextcloud-app-tasks/src/components/AppSidebar/Alarm/AlarmDateTimePickerModal.vue
  75:15  warning  Custom event name 'select-date-time' must be camelCase  vue/custom-event-name-casing

/nextcloud-app-tasks/src/components/AppSidebar/Alarm/AlarmList.vue
  128:15  warning  Custom event name 'add-alarm' must be camelCase     vue/custom-event-name-casing
  138:15  warning  Custom event name 'update-alarm' must be camelCase  vue/custom-event-name-casing
  147:15  warning  Custom event name 'remove-alarm' must be camelCase  vue/custom-event-name-casing

/nextcloud-app-tasks/src/components/AppSidebar/Alarm/AlarmListItem.vue
  213:15  warning  Custom event name 'update-alarm' must be camelCase  vue/custom-event-name-casing
  223:15  warning  Custom event name 'update-alarm' must be camelCase  vue/custom-event-name-casing
  235:15  warning  Custom event name 'remove-alarm' must be camelCase  vue/custom-event-name-casing

/nextcloud-app-tasks/src/components/AppSidebar/Alarm/AlarmListNew.vue
  217:15  warning  Custom event name 'add-alarm' must be camelCase  vue/custom-event-name-casing
  226:15  warning  Custom event name 'add-alarm' must be camelCase  vue/custom-event-name-casing

/nextcloud-app-tasks/src/components/AppSidebar/Alarm/AlarmRelativeTimePickerModal.vue
  152:15  warning  Custom event name 'select-date-time' must be camelCase  vue/custom-event-name-casing

/nextcloud-app-tasks/src/components/AppSidebar/CalendarPickerItem.vue
  111:15  warning  Custom event name 'change-calendar' must be camelCase  vue/custom-event-name-casing

/nextcloud-app-tasks/src/components/AppSidebar/CheckboxItem.vue
  31:18  warning  Custom event name 'set-checked' must be camelCase  vue/custom-event-name-casing

/nextcloud-app-tasks/src/components/AppSidebar/DateTimePickerItem.vue
  124:4  warning  Missing trailing comma  comma-dangle

/nextcloud-app-tasks/src/components/AppSidebar/MultiselectItem.vue
  103:15  warning  Custom event name 'change-value' must be camelCase  vue/custom-event-name-casing

/nextcloud-app-tasks/src/components/AppSidebar/TagsItem.vue
  92:15  warning  Custom event name 'add-tag' must be camelCase   vue/custom-event-name-casing
  95:15  warning  Custom event name 'set-tags' must be camelCase  vue/custom-event-name-casing

/nextcloud-app-tasks/src/components/TaskCheckbox.vue
  100:15  warning  Custom event name 'toggle-completed' must be camelCase  vue/custom-event-name-casing

/nextcloud-app-tasks/src/components/TaskStatusDisplay.vue
  89:15  warning  Custom event name 'status-clicked' must be camelCase  vue/custom-event-name-casing
  99:19  warning  Custom event name 'reset-status' must be camelCase    vue/custom-event-name-casing

/nextcloud-app-tasks/src/utils/dateStrings.js
  30:1  warning  The type 'Task' is undefined  jsdoc/no-undefined-types
  91:1  warning  The type 'Task' is undefined  jsdoc/no-undefined-types

/nextcloud-app-tasks/src/views/AppSidebar.vue
  175:21  warning  Expected to be enclosed by double quotes  vue/html-quotes

✖ 23 problems (0 errors, 23 warnings)
  0 errors and 2 warnings potentially fixable with the `--fix` option.