Remove "extends IHostedService" from classes where it's not required (#236)

Originally, these classes were services because I thought that all
DI-resolvable classes need to be services. However, this is not true, so
we can make these classes (notably Utility and GuildDataService) not
extend anything. `UtilityService` was renamed to `Utility` for
simplicity

---------

Signed-off-by: Octol1ttle <l1ttleofficial@outlook.com>

src/Services/GuildDataService.cs

@@ -11,7 +11,7 @@ namespace Octobot.Services;
 /// <summary>
 ///     Handles saving, loading, initializing and providing <see cref="GuildData" />.
 /// </summary>
-public sealed class GuildDataService : IHostedService
+public sealed class GuildDataService
 {
     private readonly ConcurrentDictionary<Snowflake, GuildData> _datas = new();
     private readonly ILogger<GuildDataService> _logger;
@@ -24,16 +24,6 @@ public sealed class GuildDataService : IHostedService
         lifetime.ApplicationStopping.Register(ApplicationStopping);
     }
 
-    public Task StartAsync(CancellationToken ct)
-    {
-        return Task.CompletedTask;
-    }
-
-    public Task StopAsync(CancellationToken ct)
-    {
-        return Task.CompletedTask;
-    }
-
     private void ApplicationStopping()
     {
         SaveAsync(CancellationToken.None).GetAwaiter().GetResult();

src/Services/Update/MemberUpdateService.cs

@@ -30,10 +30,10 @@ public sealed partial class MemberUpdateService : BackgroundService
     private readonly IDiscordRestGuildAPI _guildApi;
     private readonly GuildDataService _guildData;
     private readonly ILogger<MemberUpdateService> _logger;
-    private readonly UtilityService _utility;
+    private readonly Utility _utility;
 
     public MemberUpdateService(IDiscordRestChannelAPI channelApi, IDiscordRestGuildAPI guildApi,
-        GuildDataService guildData, ILogger<MemberUpdateService> logger, UtilityService utility)
+        GuildDataService guildData, ILogger<MemberUpdateService> logger, Utility utility)
     {
         _channelApi = channelApi;
         _guildApi = guildApi;

src/Services/Update/ScheduledEventUpdateService.cs

@@ -19,10 +19,10 @@ public sealed class ScheduledEventUpdateService : BackgroundService
     private readonly IDiscordRestGuildScheduledEventAPI _eventApi;
     private readonly GuildDataService _guildData;
     private readonly ILogger<ScheduledEventUpdateService> _logger;
-    private readonly UtilityService _utility;
+    private readonly Utility _utility;
 
     public ScheduledEventUpdateService(IDiscordRestChannelAPI channelApi, IDiscordRestGuildScheduledEventAPI eventApi,
-        GuildDataService guildData, ILogger<ScheduledEventUpdateService> logger, UtilityService utility)
+        GuildDataService guildData, ILogger<ScheduledEventUpdateService> logger, Utility utility)
     {
         _channelApi = channelApi;
         _eventApi = eventApi;

src/Services/Utility.cs

@@ -1,7 +1,6 @@
 using System.Drawing;
 using System.Text;
 using System.Text.Json.Nodes;
-using Microsoft.Extensions.Hosting;
 using Octobot.Data;
 using Octobot.Extensions;
 using Remora.Discord.API.Abstractions.Objects;
@@ -17,14 +16,14 @@ namespace Octobot.Services;
 ///     Provides utility methods that cannot be transformed to extension methods because they require usage
 ///     of some Discord APIs.
 /// </summary>
-public sealed class UtilityService : IHostedService
+public sealed class Utility
 {
     private readonly IDiscordRestChannelAPI _channelApi;
     private readonly IDiscordRestGuildScheduledEventAPI _eventApi;
     private readonly IDiscordRestGuildAPI _guildApi;
     private readonly IDiscordRestUserAPI _userApi;
 
-    public UtilityService(
+    public Utility(
         IDiscordRestChannelAPI channelApi, IDiscordRestGuildScheduledEventAPI eventApi, IDiscordRestGuildAPI guildApi,
         IDiscordRestUserAPI userApi)
     {
@@ -34,16 +33,6 @@ public sealed class UtilityService : IHostedService
         _userApi = userApi;
     }
 
-    public Task StartAsync(CancellationToken ct)
-    {
-        return Task.CompletedTask;
-    }
-
-    public Task StopAsync(CancellationToken ct)
-    {
-        return Task.CompletedTask;
-    }
-
     /// <summary>
     ///     Checks whether or not a member can interact with another member
     /// </summary>