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/MessageReceivedResponder.cs

@@ -0,0 +1,39 @@
+using JetBrains.Annotations;
+using Remora.Discord.API.Abstractions.Gateway.Events;
+using Remora.Discord.API.Abstractions.Rest;
+using Remora.Discord.Gateway.Responders;
+using Remora.Rest.Core;
+using Remora.Results;
+
+namespace TeamOctolings.Octobot.Responders;
+
+/// <summary>
+///     Handles sending replies to easter egg messages.
+/// </summary>
+[UsedImplicitly]
+public class MessageCreateResponder : IResponder<IMessageCreate>
+{
+    private readonly IDiscordRestChannelAPI _channelApi;
+
+    public MessageCreateResponder(IDiscordRestChannelAPI channelApi)
+    {
+        _channelApi = channelApi;
+    }
+
+    public Task<Result> RespondAsync(IMessageCreate gatewayEvent, CancellationToken ct = default)
+    {
+        _ = _channelApi.CreateMessageAsync(
+            gatewayEvent.ChannelID, ct: ct, content: gatewayEvent.Content.ToLowerInvariant() switch
+            {
+                "whoami" => "`nobody`",
+                "сука !!" => "`root`",
+                "воооо" => "`removing /...`",
+                "пон" => "https://i.ibb.co/Kw6QVcw/parry.jpg",
+                "++++" => "#",
+                "осу" => "https://github.com/ppy/osu",
+                "лан" => "https://i.ibb.co/VYH2QLc/lan.jpg",
+                _ => default(Optional<string>)
+            });
+        return Task.FromResult(Result.Success);
+    }
+}