Text direction for literals

[HadrienGardeur]

In our current version of the manifest, we don't have the ability to indicate the direction of literals.

There has been many discussions in the past about this within W3C, but it seems that things are finally moving in the right direction: https://github.com/w3c/pub-manifest/issues/75

If JSON-LD 1.1 introduces @direction:

• this will become immediately usable for us in metadata
• we'll need to explore how @direction behaves in language maps, which we use extensively for indicating language variants of a given literal
• the use of @value and @direction instead of a literal could affect how metadata are parsed and processed, so we'll need to be extra careful about that

Since we're already using JSON-LD 1.1, we won't need to bump our version.

[HadrienGardeur]

Use of @direction in language maps was deferred within the JSON-LD WG: https://github.com/w3c/json-ld-syntax/issues/280