feat: introduce binding generator

A squash of hundreds of commits with a binding API generator.

The API generator works with a hybrid model:
1. We define methods and fields in the code.
2. Mark them with API annotations.
3. For specific use cases, we use the old approach with JNI generation comments.

There is also an API to generate an AST tree, which is saved to JSON.
This JSON can be used for full API generation by declaring only field/method names.
Currently, it is used to generate constants.

By eyeballing, 95% of the API has been converted to the new approach.
This is sufficient for the current moment. Only edge cases with specific API calls are left.

fix: ambiguous call for ImGui::GetColorU32

build: disable checkstyle for imgui-binding module

Since the module is heavily generated, checkstyle for it doesn't make sense.

build: make buildSrc to use JDK 11

build: make generateApi optional when compiling project

Initially generated module was not included to the project VCS.
Since it's now in the separate src folder, we don't need to call generator every time.
Only when a new generation result is required.

imgui-binding/src/main/java/imgui/internal/flag/ImGuiItemFlags.java

@@ -1,36 +1,17 @@
 package imgui.internal.flag;
 
+import imgui.binding.annotation.BindingAstEnum;
+import imgui.binding.annotation.BindingSource;
+
 /**
  * Transient per-window flags, reset at the beginning of the frame. For child window, inherited from parent on first Begin().
  * This is going to be exposed in imgui.h when stabilized enough.
  */
+@BindingSource
 public final class ImGuiItemFlags {
     private ImGuiItemFlags() {
     }
 
-    public static final int None = 0;
-    public static final int NoTabStop = 1;
-    /**
-     * Button() will return true multiple times based on io.KeyRepeatDelay and io.KeyRepeatRate settings.
-     */
-    public static final int ButtonRepeat = 1 << 1;
-    /**
-     * [BETA] Disable interactions but doesn't affect visuals yet. See github.com/ocornut/imgui/issues/211
-     */
-    public static final int Disabled = 1 << 2;
-    public static final int NoNav = 1 << 3;
-    public static final int NoNavDefaultFocus = 1 << 4;
-    /**
-     * MenuItem/Selectable() automatically closes current Popup window
-     */
-    public static final int SelectableDontClosePopup = 1 << 5;
-    /**
-     * [BETA] Represent a mixed/indeterminate value, generally multi-selection where values differ.
-     * Currently only supported by Checkbox() (later should support all sorts of widgets)
-     */
-    public static final int MixedValue = 1 << 6;
-    /**
-     * [ALPHA] Allow hovering interactions but underlying value is not changed.
-     */
-    public static final int ReadOnly = 1 << 7;
+    @BindingAstEnum(file = "ast-imgui_internal.json", qualType = "ImGuiItemFlags_")
+    public Void __;
 }