More metadata for each locale

[matthewmayer]

follows on from #1978
related to #1984

I would like to see more metadata added for each locale, for example:

{
title:"German (Austria)",
endonym:"Deutsch (Österreich)", //in native language
code:"de_AT", //same as locale key
language:"de", //ISO_639-1
country:"AT", //ISO 3166-1 alpha-2. omitted if no country
rtl:false, //right-to-left
script:"Latn" //ISO_15924
}

I would be happy to implement this but maybe can get some feedback on the naming of the keys and values first?

[Shinigami92]

Especially the code can be used again for improved real checks for

faker/test/locale-imports.spec.ts

Lines 15 to 17 in 9bf0a6d

	expect(faker.definitions.metadata.title).toBe(
	allLocales[locale].metadata.title
	);

(and below)

[ST-DDT]

Do we require all fields?
Because if we do then we make creating custom locales harder and harder.
There are two approaches to that problem:

1. Make MetadataDefinitions optional and Partial and only require it for our own locales.
2. Create a customMetadata method or similar that can be used to create Metadata instances more easily.

I somewhat prefer 1.

[matthewmayer]

Do we require all fields? Because if we do then we make creating custom locales harder and harder. There are two approaches to that problem:

1. Make MetadataDefinitions optional and Partial and only require it for our own locales.
2. Create a customMetadata method or similar that can be used to create Metadata instances more easily.

I somewhat prefer 1.

also prefer 1.

[matthewmayer]

i think all built in locales (except base) should be able to fill in all properties except for country, which would only be for say en_AU and not en.

[matthewmayer]

might also need an optional "variant" to handle en_AU_ocker and en_BORK