refactor: 重构trustlog-sdk目录结构到trustlog/go-trustlog

- 将所有trustlog-sdk文件移动到trustlog/go-trustlog/目录
- 更新README中所有import路径从trustlog-sdk改为go-trustlog
- 更新cookiecutter配置文件中的项目名称
- 更新根目录.lefthook.yml以引用新位置的配置
- 添加go.sum文件到版本控制
- 删除过时的示例文件

这次重构与trustlog-server保持一致的目录结构，
为未来支持多语言SDK（Python、Java等）预留空间。

.editorconfig

@@ -0,0 +1,23 @@
+# Check http://editorconfig.org for more information
+# This is the main config file for this project:
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+indent_style = tab
+indent_size = 4
+trim_trailing_whitespace = true
+
+[Makefile]
+indent_style = tab  # older versions of GNU Make do not work well with spaces
+
+[*.{yaml,yml}]
+indent_size = 2
+
+[*.{md,rst}]
+trim_trailing_whitespace = false
+
+[*.{diff,patch}]
+trim_trailing_whitespace = false