Support to I18n messages

[fbenevides]

Subsystem Ktor-features/ktor-i18n

Motivation Ktor doesn't have support to i18n messages by default, yet. So, this PR creates a new feature to support that.

Solution Using Accept-Language header provided on HTTP requests (as RFC 3282 explains), we can set a localized message bundle.

Features of this PR:

• Creates a new feature called I18n - it could be installed by using:

install(I18n) {
  defaultLanguage = "pt-BR"
  encoding = StandardCharsets.UTF_8
}

• Provides a way to set an defaultLanguage and encoding
• Creates extensions in ApplicationCall to help translation on Ktor routes.
• Reads resources/messages directory to manage message bundles

[stale[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[awayo]

It's a shame that this feature had been abandoned

[fbenevides]

any idea on when we can review this PR?

[fbenevides]

News on that? Anything I can help with?

[e5l]

Hey @bjhham, I just rebased and updated the API. Could you take a fresh look?