feat: handle timezones and conversions with NodaTime

Oqtane.Client/Services/Interfaces/ITimeZoneService.cs

@@ -1,18 +0,0 @@
-using System.Collections.Generic;
-using System.Threading.Tasks;
-using Oqtane.Models;
-
-namespace Oqtane.Services
-{
-    /// <summary>
-    /// Service to store and retrieve <see cref="TimeZone"/> entries
-    /// </summary>
-    public interface ITimeZoneService
-    {
-        /// <summary>
-        /// Get the list of time zones
-        /// </summary>
-        /// <returns></returns>
-        Task<List<TimeZone>> GetTimeZonesAsync();
-    }
-}