chore: add raii, tables code from OtterGui into new Dalamud.Interface assembly

Dalamud.Interface/Raii/Font.cs

@@ -0,0 +1,51 @@
+using ImGuiNET;
+
+namespace Dalamud.Interface.Raii;
+
+// Push an arbitrary amount of fonts into an object that are all popped when it is disposed.
+// If condition is false, no font is pushed.
+public static partial class ImRaii
+{
+    public static Font PushFont(ImFontPtr font, bool condition = true)
+        => condition ? new Font().Push(font) : new Font();
+
+    // Push the default font if any other font is currently pushed.
+    public static Font DefaultFont()
+        => new Font().Push(Font.DefaultPushed, Font.FontPushCounter > 0);
+
+    public sealed class Font : IDisposable
+    {
+        internal static int        FontPushCounter = 0;
+        internal static ImFontPtr DefaultPushed;
+
+        private int _count;
+
+        public Font()
+            => this._count = 0;
+
+        public Font Push(ImFontPtr font, bool condition = true)
+        {
+            if (condition)
+            {
+                if (FontPushCounter++ == 0)
+                    DefaultPushed = ImGui.GetFont();
+                ImGui.PushFont(font);
+                ++this._count;
+            }
+
+            return this;
+        }
+
+        public void Pop(int num = 1)
+        {
+            num             =  Math.Min(num, this._count);
+            this._count          -= num;
+            FontPushCounter -= num;
+            while (num-- > 0)
+                ImGui.PopFont();
+        }
+
+        public void Dispose()
+            => this.Pop(this._count);
+    }
+}