[feature] - migration tools

[jhonny-me]

create a separate command app that reverse the process:

• read from iOS Localizable.strings files and generate an excel
• read from Android strings.xml files and generate an excel
• uses can upload/copypaste the excel to google sheet

This will helps existing projects to adopt Mirrorrim.

[jhonny-me]

implementation logic:

1. read input directory from user input
2. list out all files/subfolders in the input directory
3. matching the language string files with names
4. enumerate the matched files to generate an array of matching translations
5. merge the arrays that generated for each string file
6. write the merged array to an excel file

Detail logic about step 4:

data model

{
  "key": "some_key",
  "en": "en wordings",
  "zh":  "zh wordings",
  ....
}

[jhonny-me]

closing as done.