Add typescript

Start adding some typescript to this packages

See merge request !11

# Conflicts:
#   schema.graphql

fix: remove duplicate property definition

See merge request xpub/shared-data-model!5

Avoid duplicating the types in the readme as the information will go out of date

The shared data model as decided in Cambridge

See merge request xpub/shared-data-model!4

Remove bidirectional linking of types.

See merge request xpub/shared-data-model!1

Remove Id suffixes on properties.

Use Manuscript instead of Article, as per discussion here: pubsweet#370 (comment 17912)