Add glob and !env features

[samuel-deal-tisseo]

Hello.

Here a rework of your library with the additional features

• it allows to use env vars tags (ex: !env HOME )
• it allows to use glob patterns (ex: !include "**/*.yaml" )
• the binary include local .env file

Technically:

• those features are under feature flags
• the base64 include is now also under feature flag
• I splitted the bin and the lib into separated crates
• I used serde_yaml_ng instead of the deprecated serde_yaml
• I replaced anyhow with thiserror for the library part (because I've read somewhere that's the way to go)
• I tried to reduce the copies, but I'm not sure I've been good at this job

Context:

I liked your library but I needed some additional features.
So I forked and I have tuned it my way.
It's my first rust project so even if I tried to make it the best I could, the code should be reviewed.

I'm really sorry this looks more like a rewrite than a feature push.
I had to give it to you back, because it would not exists without your prior work.

Any feedback is welcome if you have time

[leNEKO]

Hey, thank you very much having reach me with this, that's very cool.
But i am not sure i would maintain these additional features, i think it is better option for you to maintain your own fork. I will keep an eye on it :)