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/Extensions/DiffPaneModelExtensions.cs

@@ -0,0 +1,31 @@
+using System.Text;
+using DiffPlex.DiffBuilder.Model;
+
+namespace TeamOctolings.Octobot.Extensions;
+
+public static class DiffPaneModelExtensions
+{
+    public static string AsMarkdown(this DiffPaneModel model)
+    {
+        var builder = new StringBuilder();
+        foreach (var line in model.Lines)
+        {
+            if (line.Type is ChangeType.Deleted)
+            {
+                builder.Append("-- ");
+            }
+
+            if (line.Type is ChangeType.Inserted)
+            {
+                builder.Append("++ ");
+            }
+
+            if (line.Type is not ChangeType.Imaginary)
+            {
+                builder.AppendLine(line.Text.SanitizeForDiffBlock());
+            }
+        }
+
+        return builder.ToString().InBlockCode("diff");
+    }
+}