Add support for other HTTP schemes as defined by RFC 7235

[derevnjuk]

Add support for other HTTP schemes as defined by RFC 7235 and HTTP Authentication Scheme Registry for the HTTP security schema in OAS3.

Here's an example of the Digest schema:

Authorization: Digest username="Mufasa",
       realm="http-auth@example.org",
       uri="/dir/index.html",
       algorithm=SHA-256,
       nonce="7ypf/xlj9XXwfDPEoM4URrv/xwf94BcCAzFZH4GiTo0v",
       nc=00000001,
       cnonce="f2/wE4q74E6zIJEtWaHKaf5wv/H5QzzpXusqGemxURZJ",
       qop=auth,
       response="753927fa0e85d155564e2e272a28d1802ca10daf449
          6794697cf8db5856cb6c1",
       opaque="FQhe/qaU925kfnzjCev0ciny7QMkPqMAFRtzCUYo5tdS"

It could be represented in the OAS specification as follows:

securitySchemes:
  Basic:
    type: http
    scheme: digest