Add a filter of Customer Custom Fields to Manage Tickets Page and make it Exportable

We need the custom fields added against customers, such as the Delivery Code, to be available as a search filter on the Manage Tickets page. These fields should also be displayed as a separate column on the Manage Tickets listing page and included when exporting reports to Excel.

As the Delivery Code is the unique identifier for our customers, this is required so we can identify which sites are awaiting Pending Quote Approval and provide a clear, structured report to external stakeholders like BUPA (BUPA requires this report), allowing them to see site numbers and track pending approvals.

The report should include ticket details such as date, ticket number, make, model, serial number, price, status, and the customer Delivery Code.