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/Commands/Events/ErrorLoggingPostExecutionEvent.cs

@@ -0,0 +1,88 @@
+using JetBrains.Annotations;
+using Microsoft.Extensions.Logging;
+using Remora.Discord.API.Abstractions.Objects;
+using Remora.Discord.API.Abstractions.Rest;
+using Remora.Discord.API.Objects;
+using Remora.Discord.Commands.Contexts;
+using Remora.Discord.Commands.Feedback.Messages;
+using Remora.Discord.Commands.Feedback.Services;
+using Remora.Discord.Commands.Services;
+using Remora.Discord.Extensions.Embeds;
+using Remora.Discord.Extensions.Formatting;
+using Remora.Results;
+using TeamOctolings.Octobot.Extensions;
+
+namespace TeamOctolings.Octobot.Commands.Events;
+
+/// <summary>
+///     Handles error logging for slash command groups.
+/// </summary>
+[UsedImplicitly]
+public class ErrorLoggingPostExecutionEvent : IPostExecutionEvent
+{
+    private readonly IFeedbackService _feedback;
+    private readonly ILogger<ErrorLoggingPostExecutionEvent> _logger;
+    private readonly IDiscordRestUserAPI _userApi;
+
+    public ErrorLoggingPostExecutionEvent(ILogger<ErrorLoggingPostExecutionEvent> logger, IFeedbackService feedback,
+        IDiscordRestUserAPI userApi)
+    {
+        _logger = logger;
+        _feedback = feedback;
+        _userApi = userApi;
+    }
+
+    /// <summary>
+    ///     Logs a warning using the injected <see cref="ILogger" /> if the <paramref name="commandResult" /> has not
+    ///     succeeded.
+    /// </summary>
+    /// <param name="context">The context of the slash command.</param>
+    /// <param name="commandResult">The result whose success is checked.</param>
+    /// <param name="ct">The cancellation token for this operation. Unused.</param>
+    /// <returns>A result which has succeeded.</returns>
+    public async Task<Result> AfterExecutionAsync(
+        ICommandContext context, IResult commandResult, CancellationToken ct = default)
+    {
+        _logger.LogResult(commandResult, $"Error in slash command execution for /{context.Command.Command.Node.Key}.");
+
+        var result = commandResult;
+        while (result.Inner is not null)
+        {
+            result = result.Inner;
+        }
+
+        if (result.IsSuccess)
+        {
+            return Result.Success;
+        }
+
+        var botResult = await _userApi.GetCurrentUserAsync(ct);
+        if (!botResult.IsDefined(out var bot))
+        {
+            return ResultExtensions.FromError(botResult);
+        }
+
+        var embed = new EmbedBuilder().WithSmallTitle(Messages.CommandExecutionFailed, bot)
+            .WithDescription(Markdown.InlineCode(result.Error.Message))
+            .WithFooter(Messages.ContactDevelopers)
+            .WithColour(ColorsList.Red)
+            .Build();
+
+        var issuesButton = new ButtonComponent(
+            ButtonComponentStyle.Link,
+            BuildInfo.IsDirty
+                ? Messages.ButtonDirty
+                : Messages.ButtonReportIssue,
+            new PartialEmoji(Name: "\u26a0\ufe0f"), // 'WARNING SIGN' (U+26A0)
+            URL: BuildInfo.IssuesUrl,
+            IsDisabled: BuildInfo.IsDirty
+        );
+
+        return ResultExtensions.FromError(await _feedback.SendContextualEmbedResultAsync(embed,
+            new FeedbackMessageOptions(MessageComponents: new[]
+            {
+                new ActionRowComponent(new[] { issuesButton })
+            }), ct)
+        );
+    }
+}