Add command to announce requests

[Javggg]

Similar to what zzuf did with #57, this PR adds the /requests announce command from the Requests plugin.

Usage: /requests announce [--name|-n]

By default the announcement reads "We are accepting map requests". With the --name flag, it credits the staff member who ran it.

[applenick]

The formatting feels a bit outdated. Also, having a staff member's name attached to accepting map requests seems unnecessary as presenting a unified staff front is probably the better approach today. Could you remove the --name flag?

As for formatting, I'd go for something like this and making it a clickable component:

Component announce = text()
    .append(text("Map requests are now ", NamedTextColor.GRAY))
    .append(text("OPEN", NamedTextColor.GREEN, TextDecoration.BOLD))
    .append(text("! ", NamedTextColor.GRAY))
    .append(text("[", NamedTextColor.GRAY))
    .append(text("Request a map", NamedTextColor.AQUA))
    .append(text("]", NamedTextColor.GRAY))
    .clickEvent(ClickEvent.suggestCommand("/request "))
    .hoverEvent(HoverEvent.showText(text("Click to request a map", NamedTextColor.GRAY)))
    .build();

I wonder if in addition to bringing back the dedicated announcement command, we could simply auto-broadcast whenever a staff member enables requests. That way, there’s one less manual step, but likely better to have both options available.

Thanks for taking the time to work on this!