feat: add support for attachments in template management

- Enhanced TemplateEditForm to include attachments in the template data.
- Updated createDocumentFromTemplate to handle attachment creation.
- Modified updateTemplate to manage attachment updates and deletions.
- Integrated attachments into ZTemplateSchema and ZAddTemplateSettingsFormSchema for validation.
- Improved getTemplateById to fetch attachments alongside other template data.

packages/prisma/schema.prisma

@@ -312,6 +312,8 @@ enum DocumentVisibility {
   ADMIN
 }
 
+// Only "LINK" is supported for now. 
+// All other attachment types are not yet supported.
 enum AttachmentType {
   FILE
   VIDEO