Replace hud_reloadscheme hack with EditablePanel + LoadControlSettings, indirectly fixes MOTD title + layout

[nullsystem]

• Both ammo and health-aux huds had a hack which forces hud_reloadscheme to be called on initialization. However this has visibly caused an issue with the MOTD which in Valve's code resets the data and look a bit odd. This also enforced reload on all huds which is unnecessary.
• The proper way to load those HudLayout.res settings is instead to have those inherit EditablePanel which most importantly provides a method LoadControlSettings to properly load those settings instead.
• This also refactor the font applying to ApplySchemeSettings
• Minor edit in HudLayout.res chat box is intentional otherwise there's a permanent background with using this EditablePanel change.
• fixes #367

Testing

• What to change around:
  • Change/add around values in: scripts/HudLayout.res. Minimal example to differentiate from defaults. Compass +20 instead of +3, Ammo read bg, Health bar RGB, 255-0-255:

    NHudCompass
    {
            "fieldName"             "NHudCompass"
            "y_bottom_pos"          "20"
    }
    NHudWeapon
    {
            "fieldName"             "NHudWeapon"
            "box_color_r"           "254"
    }
    NHudHealth
    {
            "fieldName"             "NHudHealth"
            "health_color_g"        "0"
    }

• What needed to be checked:
  • First time loading in, make sure HudLayout.res setting is applied
  • hud_reloadscheme works as usual
  • N-times loading in, HudLayout.res setting is applied
  • Without PR #366 the MOTD retains its layout and server title. It doesn't display something in the central area but that's part of that PR's change. With PR #366 it should look functional.

[Rainyan]

Also seems we've a merge conflict to be resolved.

[nullsystem]

@Rainyan Actually, only the server title/contents being intact being the main fix of this regarding MOTD. So I shouldn't really have mentioned the layout stuff. Technically though, the 2nd picture's "broken" layout is the "actual" res layout of the MOTD straight from OG:NT's TextWindow.res file I think. The fix is probably more like define our own one that doesn't look so bad/closer to HL2's one and also fix that vguitextwindow class to read from the res from the beginning.

So in this case, yeah out of scope of this PR.

[nullsystem]

@Rainyan Try out with the latest commit in, I think it's just moving around SetScreenSize/SetBounds lines caused it. Don't think I see the warning after the commit (but seen before) but have a check.