accept-language vs rust-i18n vs fluent4rs

Parse and compare Accept-Language header strings

Rust I18n is use Rust codegen for load YAML file storage translations on compile time, and give you a t! macro for simply get translation texts.

Parser / codec for [Fluent FTL files](https://github.com/projectfluent/fluent/blob/master/spec/fluent.ebnf), written for [lingora](https://github.com/nigeleke/lingora) (a localization management program), and may be found to be useful outside of that context. It is not intended to replace any aspects of the [fluent-rs](https://github.com/projectfluent/fluent-rs) crate implemented by [Project Fluent](https://projectfluent.org/), and, for the majority of language translation needs, the reader is referred back to that crate.