Admin Portal Reservations - Missing Additional Options and Donation Option

**Is your feature request related to a problem? Please describe.**
Currently, we face the issue that when processing ticket orders received via phone or email and filling out the reservation through the Alf.io admin portal (version v.2.0-M5-2502), we cannot add additional options or select "Donations." This limitation makes it difficult to customize orders and manage donations efficiently.

**Describe the solution you'd like**
We would like to have the ability to add additional options for tickets and directly select and manage "Donations" within the admin portal. This functionality should be available for manual reservations as well as for generating HardCopy tickets with label printing. An intuitive user interface for managing these features would be ideal.

**Describe alternatives you've considered**
One alternative would be to manually record additional options and donations in a separate system and later link them to ticket orders. However, this approach is inefficient and prone to errors. Another possibility would be using an external tool to manage donations and options, but this complicates integration and workflow.

**Additional context**
Our customers expect fast and flexible handling of their orders, especially for requests made via phone or email. The lack of support for additional options and donations in the admin portal significantly complicates this process. Screenshots of the current workflow can be provided if needed to better illustrate the issue.