GuestLog - Integrated AddressQuery dialog in GuestDocument creation and fixes.

- Added new CountryCodeUtils to map ISO-3166:Alpha2 country codes to ISO-3166:Alpha3 codes.
- Added new config for results language of AddressQuery services.

src/Somnia.GuestLog/Services/AddressQuery/NominatimAddressQueryService.cs

@@ -2,6 +2,7 @@ using Microsoft.AspNetCore.WebUtilities;
 using Microsoft.Extensions.Options;
 using Somnia.GuestLog.Models.Configuration;
 using Somnia.GuestLog.Models.DTOs;
+using Somnia.GuestLog.Utils;
 
 namespace Somnia.GuestLog.Services.AddressQuery;
 
@@ -36,6 +37,8 @@ public class NominatimAddressQueryService(
                     continue;
                 }
 
+                string? alpha3CountryCode = CountryCodesUtils.Alpha2ToAlpha3(result.Address.Country_code);
+
                 rsList.Add(new()
                 {
                     HouseNumber = result.Address.House_number,
@@ -44,7 +47,8 @@ public class NominatimAddressQueryService(
                     AddressProvince = result.Address.Province,
                     AddressState = result.Address.State,
                     AddressCountry = result.Address.Country,
-                    ZipCode = result.Address.Postcode
+                    ZipCode = result.Address.Postcode,
+                    AddressCountryCode = alpha3CountryCode
                 });
             }
 
@@ -66,7 +70,10 @@ public class NominatimAddressQueryService(
 
         client.BaseAddress = baseAddr;
         client.DefaultRequestHeaders.UserAgent.ParseAdd(config.UserAgent ?? defaultUserAgent);
-        client.DefaultRequestHeaders.AcceptLanguage.ParseAdd("es");
+        if (config.ResultLang is not null)
+        {
+            client.DefaultRequestHeaders.AcceptLanguage.ParseAdd(config.ResultLang);
+        }
 
         return client;
     }
@@ -92,7 +99,8 @@ public class NominatimAddressQueryService(
         string? Province = null,
         string? State = null,
         string? Country = null,
-        string? Postcode = null
+        string? Postcode = null,
+        string? Country_code = null
     );
 
     private record class ApiResult(