[TF2] Add ConVar for Tournament HUD to ensure client visiblity

[irql-notlessorequal]

This adds a new ConVar (cl_hud_tournament_always_centered) that creates an additional pass to CHudTournament::RecalculatePlayerPanels that when enabled and past 9 defenders, will swap out our client with a player in the middle of the panel list, ensuring that we are once again visible.

Useful for community MvM gamemodes utilizing above normal defender counts.

Before:

After and enabled:

[FlaminSarge]

It may be worth allowing this UI to overflow onto a 2nd line or use wider bounds instead, even if that would need hud file updates as well.

[irql-notlessorequal]

It may be worth allowing this UI to overflow onto a 2nd line or use wider bounds instead, even if that would need hud file updates as well.

In my opinion having it overflow into a 2nd line could work however it'd cause visual clutter, and would get worse with more defenders a community gamemode would have.

On the otherhand, using wider bounds doesn't help much for 4:3 and 5:4 users and isn't enough to for example have all 24 players be visible (maybe at 4K or higher resolutions it would?) considering the HUD does scale, see below screenshot as a proof of concept.

Maybe having a new variant of the tournament HUD that would show a percentage of the ready state of players would be a much better idea but that would be additional work.