This adds the timezones to the step validation and renders an error when an invalid timezone is imported.
How to test:
1. import a blueprint with invalid timezone "foo"
2. select a target
3. go to Registration step
4. click on "Review and finish" button
Current behaviour:
- the "Create" button is disabled, but when navigating to Timezone step no error is displayed
After update:
- there is an error rendered under the timezone select
9fdd6f0b43