OpenAPI Generated client

[devlinjunker]

Use open api files from here https://github.com/APIs-guru/openapi-directory/tree/master/APIs

ideas:

• GitHub
• Gmail
• drive
• halo?
• instagram?
• Twitter?

Generate client side classes for accessing these services

Similar to https://github.com/ocf-app/flutter_app/issues/13

[devlinjunker]

See https://github.com/devlinjunker/test.openapi.client

[devlinjunker]

dart generation seems less stable for flutter apps, how is js generation?

[devlinjunker]

External APIs should be handled in API service probably, we should just generate openapi client from our API openapi.yaml file (see devlinjunker/template.hapi.rest#12)