director OpenAPI, refactoring

[sanderegg]

What do these changes do?

Refactoring of the director REST API using the openapi protocol and API first paradigm.
Also implies migrating FLASK based server to AIOHTTP

• define open API v3.0 following good practices (use resource names without verbs, ...), separated in several files to allow re-use

• use node-meta-v0.0.1.json as defined in link New User and Project Models (schemas) #148

• Server side:

  • migrated to AIOHTTP
  • using AIOHTTP-apiset library to auto-generate routes
  • use models autogenerated from API using openapi-generator-cli
  • follow osparc best practices for dockerfile (connect (SimCoreUser) will be the new user for host&container in order to avoid being root. ID with a very high number. Mechanism that the user in the host and in docker image are the same one. #90), folder structure
  • envelope responses (always returning {data:"",status:""})
  • added middleware to generate standard errors
  • validate responses of the route /services that return the node defined by node-meta-v0.0.1.json using jsonschema
  • created re-usable scripts to autogenerate code stubs

• Client side:

  • integrated director-sdk (fixes create director client sdk #197)
  • forked AIOHTTP-apiset to fix an issue on the server side that was incorrectly triggering an error when an empty HTTP body was sent

• Webserver:

  • replaced calls to director by using the director-sdk using asyncio
  • refactored call to start pipeline to convert new node schema to old schema so that the platform runs as usual.

• Webclient:

  • merged New User and Project Models (schemas) #148

NOTE: validate openapi responses currently has an issue when using the external json-schema reference. wating for an answer from openapi-core
NOTE2: currently the json-schema is a copy from here

Related issue number

connects #185, connects #196
fixes #213, fixes #197

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes
• If you design a new module, add your user to .github/CODEOWNERS

@pcrespov , @mguidon