handle openapi 3.0 format, use new swagger-ui

[szlartibartfaszt79]

• handle openapi 3.0 format
• copy latest swagger-ui
• remove default swagger config parameter for openapi config parameter using

[elbrujohalcon]

I like this, but… don't we need to update/create some tests for this change?

[szlartibartfaszt79]

I like this, but… don't we need to update/create some tests for this change?

You're right. I fixed the failed test, but I have to extend the test cases with openapi 3.0 format.

[szlartibartfaszt79]

WIP

[szlartibartfaszt79]

Need I squash before merge?
There were two minor fixes after approval. This version is used internally for half year without any issues.

[elbrujohalcon]

Merged. Thanks @szlartibartfaszt79 :)

[szlartibartfaszt79]

Thanks for the merge :-)
Unfortunately README.md is not up-to-date according to openapi specification. Moreover it contains some wrong data, for example: swagger => "2.0". It will be fixed as soon as possible in a new PR. I apologize for the inconvenience!