Added a feature to save logs to local storage (#1741)

- Added export logs to local storage
[1664](https://github.com/tiann/KernelSU/issues/1664)

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Co-authored-by: weishu <twsxtd@gmail.com>

manager/app/src/main/res/values-zh-rCN/strings.xml

@@ -128,4 +128,5 @@
     <string name="flash_success">刷写完成</string>
     <string name="flash_failed">刷写失败</string>
     <string name="selected_lkm">选择的 LKM ：%s</string>
+    <string name="save_log">保存日志保存日志</string>
 </resources>