Add issue button w/ some button updates (#221)

In this PR, I've added a "Report an issue" button and a few more
button-related changes:
- Add "Report an issue" button
- Add icon for "Octobot's source code"
- Rename `AboutTitleRepository` to `ButtonOpenRepository`
- Rename `OpenEventInfoButton` to `ButtonOpenEventInfo` to be consistent
with other language string names
- Rename `ColorsList.cs` to `Miscellaneous.cs`
- Add public const strings in `Octobot.cs` to get repository & issues links

---------

Signed-off-by: mctaylors <cantsendmails@mctaylors.ru>

src/Responders/GuildLoadedResponder.cs

@@ -7,6 +7,7 @@ using Remora.Discord.API.Abstractions.Gateway.Events;
 using Remora.Discord.API.Abstractions.Objects;
 using Remora.Discord.API.Abstractions.Rest;
 using Remora.Discord.API.Gateway.Events;
+using Remora.Discord.API.Objects;
 using Remora.Discord.Extensions.Embeds;
 using Remora.Discord.Gateway.Responders;
 using Remora.Results;
@@ -112,7 +113,14 @@ public class GuildLoadedResponder : IResponder<IGuildCreate>
             .WithColour(ColorsList.Red)
             .Build();
 
-        return await _channelApi.CreateMessageWithEmbedResultAsync(
-            channel, embedResult: errorEmbed, ct: ct);
+        var issuesButton = new ButtonComponent(
+            ButtonComponentStyle.Link,
+            Messages.ButtonReportIssue,
+            new PartialEmoji(Name: "⚠️"),
+            URL: Octobot.IssuesUrl
+        );
+
+        return await _channelApi.CreateMessageWithEmbedResultAsync(channel, embedResult: errorEmbed,
+            components: new[] { new ActionRowComponent(new[] { issuesButton }) }, ct: ct);
     }
 }