Dependency localization

[SamRodri]

Implement a way for lib crates to export Fluent files.

The scrapper must find these files, the name must be unique

[SamRodri]

Questions:

• How updates work?
  • Replace template, pseudos, don't touch translations.
  • Implement tooling that compares template keys with translations.
    • Potential issue here, base language not translated when not needed, discourage this?
• Support multiple versions of dependency?
  • Only for breaking changes (keys removed).

API design:

• cargo zng l10n --package=foo OR --manifest-path=foo/Cargo.toml scraps foo/src/**/*.rs to foo/l10n.
• With --deps copies dependencies to foo/l10n/deps/{pkg-name}/ and foo/l10n/{lang}/deps/{pkg-name}/.
  • Deps dirs in dependencies are merged, {dep}/l10n/deps/ are copied to foo/l10n/deps, copies after all dependencies copied, does not override files, alphabetic order.
• l10n! embeds CARGO_PKG_NAME, resolver uses it to search for deps dir first.

[SamRodri]

Final API:

• cargo zng l10n --package=foo OR --manifest-path=foo/Cargo.toml scraps foo/src/**/*.rs to foo/l10n.
• --deps copies dependencies to foo/l10n/{lang}/deps/{dep.name}/{dep.version}/.
  • cargo zng l10n generated deps dirs have a .gitignore.
  • Deps dirs in dependencies are merged, {dep}/l10n/deps/ are copied to foo/l10n/deps, copies after all dependencies copied, does not override files, applies in alphabetical order, newer version first.
  • Unamed (lang.ftl) files are renamed to the multi file style (_.ftl).
• l10n! embeds CARGO_PKG_NAME and CARGO_PKG_VERSION, resolver uses it to search for deps dir for nearest version.
• Pseudos are an utility, generated from other locales using cargo zng l10n --pseudo*.