[Bug] Add back command to set up verification buttons

[stepech]

Idk how, but somehow it got lost when switching from Commands to SlashCommands

[stepech]

Inspiration can be taken from:

honza-botner/src/HonzaBotner.Discord.Services/Commands/MessageCommands.cs

Lines 232 to 293 in b62ca96

	public class ButtonCommands : BaseCommandModule
	{
	private readonly IButtonManager _buttonManager;
	public ButtonCommands(IButtonManager manager)
	{
	_buttonManager = manager;
	}
	[Description("Deletes all button interactions on the message")]
	[Command("remove")]
	public async Task RemoveButtons(CommandContext ctx, [Description("URL of the message")] string url)
	{
	DiscordGuild guild = ctx.Guild;
	DiscordMessage? message = await DiscordHelper.FindMessageFromLink(guild, url);
	if (message == null)
	{
	throw new ArgumentOutOfRangeException($"Couldn't find message with link: {url}");
	}
	try
	{
	await _buttonManager.RemoveButtonsFromMessage(message);
	}
	catch (UnauthorizedException)
	{
	await ctx.RespondAsync("Error: You can only edit messages by this bot.");
	return;
	}
	DiscordEmoji reactEmoji = DiscordEmoji.FromName(ctx.Client, ":+1:");
	await ctx.Message.CreateReactionAsync(reactEmoji);
	}
	[Description("Marks message as verification message")]
	[Command("setup")]
	public async Task SetupButtons(
	CommandContext ctx,
	[Description("URL of the message")] string url
	)
	{
	DiscordGuild guild = ctx.Guild;
	DiscordMessage? message = await DiscordHelper.FindMessageFromLink(guild, url);
	if (message == null)
	{
	throw new ArgumentOutOfRangeException($"Couldn't find message with link: {url}");
	}
	try
	{
	await _buttonManager.SetupVerificationButtons(message);
	}
	catch (UnauthorizedException)
	{
	await ctx.RespondAsync("Error: You can only edit messages by this bot.");
	return;
	}
	DiscordEmoji reactEmoji = DiscordEmoji.FromName(ctx.Client, ":+1:");
	await ctx.Message.CreateReactionAsync(reactEmoji);
	}
	}

[stepech]

In case we proceed with a plan discussed in discord to change the way verification works, this might actually be a fix that would be useful just for one app version and then removed with potential rewrite. I am thus removing it from todo for the next version.