Feature request: add additional utils for working with envfiles

[leha-bot]

The .env files are pretty neat way to pass-through some key-value pairs into program environment variables and some internal configs.
It would be great if reflect-cpp would support some load-like functionality for .env files and serializing/deserializing from/to struct, but there would be some conceptual differences comparing to yaml/json/another hierarchical formats,

Also it possilbly should add new processor UpperSnakeCaseToSnakeCase and reversed.

[liuzicheng1987]

Hi @leha-bot ,

Maybe we could wrap around this library:

https://github.com/ph3at/libenvpp

I assume by upper snake case you mean this: UPPER_SNAKE_CASE?

I don't even think you would need a special processor for that, we could just introduce UpperCase and LowerCase processors.

[leha-bot]

I actually thought about wrapping this library, as it is pretty neat for work with envs, but, AFAIK, it couldn't parse .env files

I saw the (seems long-abandoned) library https://github.com/adeharo9/cpp-dotenv/ with parser (it uses ANTLR parser)