Connexion-compatible token validation

[uniqueg]

Since Connexion 2.0, Connexion helps with validation of Swagger 2 / OpenAPI 3 security schemas. While this is in princple welcome, it inteferes with the functionality of the dedicated auth/security decorator implemented in FOCA.

In order to be compatible with Connexion, an x-{auth_method}TokenInfo field needs to be added to the securityDefinitions (Swagger 2) or securitySchemes (OpenAPI 3) objects, where {auth_method} is one of several options, depending on the version of the OpenAPI specificaiton.

This will require a major refactoring in various places (decorator in security.auth module needs to be re-factored/-implemented, the API registration needs to be udpated, and likely a lot of tests will be affected, too).