Add more logs to explain

[jauggy]

This will simply add ratings to $explain for split_noobs.

               "Perform brute force with the following players to get the best score.",
               "Players: kyutoryu (9.0), fbots1998 (2.8), jauggy (20.5), Aposis (20.4), [DTG]BamBin0 (20.1), reddragon2010 (18.4), Noody (17.6), SLOPPYGAGGER (8.9), MaTThiuS_82 (8.3), barmalev (3.6)"

The numbers in brackets are their ratings.

I'm trying to understand why the ratings don't add up to team rating in this bug:
https://discord.com/channels/549281623154229250/1332129520538615818

[jauggy]

This code inside balancer_server.ex looks sus:

    team_size =
      teams
      |> Enum.map(fn {_, t} -> Enum.count(t) end)
      |> Enum.max(fn -> 0 end)

Maybe this doesn't calculate the team_size correctly.

Let's say the lobby has 6 players team 1 and 4 players team 2 and then you press balance. I think this would think the team_size is 6 when it should be 5.