chore: 删除无用的项目配置和资源文件修改android key,修正godot4.3无法构建的问题

- 移除 .gitattributes 和 .gitignore 文件
- 删除 Asserts 目录下的棋盘和棋子基础资源文件

project.godot

@@ -1,36 +0,0 @@
-; Engine configuration file.
-; It's best edited using the editor UI and not directly,
-; since the parameters that go here are not all obvious.
-;
-; Format:
-;   [section] ; section goes between []
-;   param=value ; assign values to parameters
-
-config_version=5
-
-[application]
-
-config/name="Chinese_Chess"
-run/main_scene="res://Main.tscn"
-config/features=PackedStringArray("4.3", "C#", "Mobile")
-config/icon="res://Asserts/icon.svg"
-
-[autoload]
-
-Global="*res://Scripts/Global.cs"
-
-[display]
-
-window/size/viewport_width=720
-window/size/viewport_height=1280
-window/stretch/mode="viewport"
-window/handheld/orientation=1
-
-[dotnet]
-
-project/assembly_name="Chinese_Chess"
-
-[rendering]
-
-renderer/rendering_method="mobile"
-textures/vram_compression/import_etc2_astc=true