[Build] Change comparison for binary libraries

Instead of size we will compare hash of the `imgui-binding/src/main` folder.

bin/README.md

@@ -0,0 +1,17 @@
+Folder contains libraries used by the binding and `binding.sha1` sum of the `imgui-binding/src/main` directory libraries has been built upon.
+
+Provide `imgui.library.path` (or `java.library.path`) VM option to the folder with one of those file (ex: `-Dimgui.library.path=./folder/path`).
+In the same way you can use 'java.library.path' option instead.
+
+By default, binding expects `imgui-java64` file name.
+You can change that by using `imgui.library.name` VM option (ex: `-Dimgui.library.name=custom-lib-name.dll`).
+
+| OS      | Library               |
+|---------|-----------------------|
+| Windows | imgui-java64.dll      |
+| Linux   | libimgui-java64.so    |
+| macOS   | libimgui-java64.dylib |
+
+Freetype directory contains same libraries, but with Freetype support.
+
+Hash sum in the `binding.sha1` file is used in CI to see, if there is a need to update native binaries.