Add typed high-level ruleset and set API

src/LibNftables/NftTable.cs

@@ -0,0 +1,22 @@
+namespace LibNftables;
+
+/// <summary>
+/// Represents a typed nftables table definition.
+/// </summary>
+public sealed class NftTable
+{
+    /// <summary>
+    /// Gets or sets the nftables family for the table.
+    /// </summary>
+    public NftFamily Family { get; set; } = NftFamily.Inet;
+
+    /// <summary>
+    /// Gets or sets the table name.
+    /// </summary>
+    public string? Name { get; set; }
+
+    /// <summary>
+    /// Gets the sets declared in this table.
+    /// </summary>
+    public IList<NftSet> Sets { get; } = new List<NftSet>();
+}