CVar CharacterRequirement (#1322)

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# Description

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This takes in one CVar and one required value and simply checks if the
CVar's value as a string is equal to the required value. I could make it
use a list of them, but I really didn't think it was needed considering
CharacterAndLogic.

I also cleaned up CharacterRequirements.Profile.cs a bit.

---------

Signed-off-by: sleepyyapril <[email protected]>
Co-authored-by: VMSolidus <[email protected]>
Co-authored-by: DEATHB4DEFEAT <[email protected]>

Content.Shared/Customization/Systems/CharacterRequirements.Misc.cs

@@ -0,0 +1,55 @@
+using Content.Shared.Customization.Systems;
+using Content.Shared.Preferences;
+using Content.Shared.Roles;
+using JetBrains.Annotations;
+using Robust.Shared.Configuration;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.Customization.Systems;
+
+/// <summary>
+///     Requires the server to have a specific CVar value. 
+/// </summary>
+[UsedImplicitly, Serializable, NetSerializable,]
+public sealed partial class CVarRequirement : CharacterRequirement
+{
+    [DataField("cvar", required: true)]
+    public string CVar;
+
+    [DataField(required: true)]
+    public string RequiredValue;
+
+    public override bool IsValid(
+        JobPrototype job,
+        HumanoidCharacterProfile profile,
+        Dictionary<string, TimeSpan> playTimes,
+        bool whitelisted,
+        IPrototype prototype,
+        IEntityManager entityManager,
+        IPrototypeManager prototypeManager,
+        IConfigurationManager configManager,
+        out string? reason,
+        int depth = 0
+    )
+    {
+        if (!configManager.IsCVarRegistered(CVar))
+        {
+            reason = null;
+            return true;
+        }
+
+        const string color = "lightblue";
+        var cvar = configManager.GetCVar(CVar);
+        var isValid = cvar.ToString()! == RequiredValue;
+
+        reason = Loc.GetString(
+            "character-cvar-requirement",
+            ("inverted", Inverted),
+            ("color", color),
+            ("cvar", CVar),
+            ("value", RequiredValue));
+
+        return isValid;
+    }
+}