Apply official naming guidelines to Octobot (#306)

1. The root namespace was changed from `Octobot` to
`TeamOctolings.Octobot`:
> DO prefix namespace names with a company name to prevent namespaces
from different companies from having the same name.
2. `Octobot.cs` was renamed to `Program.cs`:
> DO NOT use the same name for a namespace and a type in that namespace.
3. `IOption`, `Option` were renamed to `IGuildOption` and `GuildOption`
respectively:
> DO NOT introduce generic type names such as Element, Node, Log, and
Message.
4. `Utility` was moved out of the `Services` namespace. It didn't belong
there anyway
5. `Program` static fields were moved to `Utility`
6. Localisation files were moved back to the project source files. Looks
like this fixed `Message.Designer.cs` code generation

---------

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

TeamOctolings.Octobot/Responders/MessageDeletedResponder.cs

@@ -0,0 +1,107 @@
+using System.Text;
+using JetBrains.Annotations;
+using Remora.Discord.API.Abstractions.Gateway.Events;
+using Remora.Discord.API.Abstractions.Objects;
+using Remora.Discord.API.Abstractions.Rest;
+using Remora.Discord.Extensions.Embeds;
+using Remora.Discord.Extensions.Formatting;
+using Remora.Discord.Gateway.Responders;
+using Remora.Results;
+using TeamOctolings.Octobot.Data;
+using TeamOctolings.Octobot.Extensions;
+using TeamOctolings.Octobot.Services;
+
+namespace TeamOctolings.Octobot.Responders;
+
+/// <summary>
+///     Handles logging the contents of a deleted message and the user who deleted the message
+///     to a guild's <see cref="GuildSettings.PrivateFeedbackChannel" /> if one is set.
+/// </summary>
+[UsedImplicitly]
+public class MessageDeletedResponder : IResponder<IMessageDelete>
+{
+    private readonly IDiscordRestAuditLogAPI _auditLogApi;
+    private readonly IDiscordRestChannelAPI _channelApi;
+    private readonly GuildDataService _guildData;
+    private readonly IDiscordRestUserAPI _userApi;
+
+    public MessageDeletedResponder(
+        IDiscordRestAuditLogAPI auditLogApi, IDiscordRestChannelAPI channelApi,
+        GuildDataService guildData, IDiscordRestUserAPI userApi)
+    {
+        _auditLogApi = auditLogApi;
+        _channelApi = channelApi;
+        _guildData = guildData;
+        _userApi = userApi;
+    }
+
+    public async Task<Result> RespondAsync(IMessageDelete gatewayEvent, CancellationToken ct = default)
+    {
+        if (!gatewayEvent.GuildID.IsDefined(out var guildId))
+        {
+            return Result.Success;
+        }
+
+        var cfg = await _guildData.GetSettings(guildId, ct);
+        if (GuildSettings.PrivateFeedbackChannel.Get(cfg).Empty())
+        {
+            return Result.Success;
+        }
+
+        var messageResult = await _channelApi.GetChannelMessageAsync(gatewayEvent.ChannelID, gatewayEvent.ID, ct);
+        if (!messageResult.IsDefined(out var message))
+        {
+            return ResultExtensions.FromError(messageResult);
+        }
+
+        if (string.IsNullOrWhiteSpace(message.Content))
+        {
+            return Result.Success;
+        }
+
+        var auditLogResult = await _auditLogApi.GetGuildAuditLogAsync(
+            guildId, actionType: AuditLogEvent.MessageDelete, limit: 1, ct: ct);
+        if (!auditLogResult.IsDefined(out var auditLogPage))
+        {
+            return ResultExtensions.FromError(auditLogResult);
+        }
+
+        var auditLog = auditLogPage.AuditLogEntries.Single();
+
+        var deleterResult = Result<IUser>.FromSuccess(message.Author);
+        if (auditLog.UserID is not null
+            && auditLog.Options.Value.ChannelID == gatewayEvent.ChannelID
+            && DateTimeOffset.UtcNow.Subtract(auditLog.ID.Timestamp).TotalSeconds <= 2)
+        {
+            deleterResult = await _userApi.GetUserAsync(auditLog.UserID.Value, ct);
+        }
+
+        if (!deleterResult.IsDefined(out var deleter))
+        {
+            return ResultExtensions.FromError(deleterResult);
+        }
+
+        Messages.Culture = GuildSettings.Language.Get(cfg);
+
+        var builder = new StringBuilder()
+            .AppendLine(message.Content.InBlockCode())
+            .AppendLine(
+                string.Format(Messages.DescriptionActionJumpToChannel, Mention.Channel(gatewayEvent.ChannelID))
+            );
+
+        var embed = new EmbedBuilder()
+            .WithSmallTitle(
+                string.Format(
+                    Messages.CachedMessageDeleted,
+                    message.Author.GetTag()), message.Author)
+            .WithDescription(builder.ToString())
+            .WithActionFooter(deleter)
+            .WithTimestamp(message.Timestamp)
+            .WithColour(ColorsList.Red)
+            .Build();
+
+        return await _channelApi.CreateMessageWithEmbedResultAsync(
+            GuildSettings.PrivateFeedbackChannel.Get(cfg), embedResult: embed,
+            allowedMentions: Utility.NoMentions, ct: ct);
+    }
+}