confgen: add debugging info just like source map to report accurate positions of original Excel/CSV

[wenchy]

Problem

confgen:

table -> JSON/Text/Bin -> In-memory Object

The checker or validate apply on the generated object, cannot known the accurate postions of original table cell.

SourceMap

In web dev, to help with debugging, these source map files contain essential information about how the compiled code maps to the original code.
A source map is a JSON file format that maps between minified or transformed code received by the browser and its original unmodified form, allowing the original code to be reconstructed and used when debugging.

• https://github.com/tc39/ecma426
• https://web.dev/articles/source-maps
• https://developer.mozilla.org/en-US/docs/Glossary/Source_map
• Decoding and Encoding Base64 VLQs in Source Maps
• Yet another explanation on sourcemap