Authorization header for uaa needs oauth2 encoding now

UAA changes now to standard oauth encoding:
The RFC for OAuth requires an URL encode in authorization header, see
https://tools.ietf.org/html/rfc6749#section-2.3

The authorization header needs to be
Authorization: Basic base64Encode(urlencode(client_id):urlencode(client_secret))

UAAC does not encode the authorization header. (client)
UAA does not decode the authorization header (server)
Thus this issue does popup in uaac before, however uaac should behave standard conform.

see
https://github.com/cloudfoundry/cf-java-client/blob/master/cloudfoundry-client-reactor/src/main/java/org/cloudfoundry/reactor/tokenprovider/AbstractUaaTokenProvider.java#L185-L187

This will come with UAA-RELEASE 74.0.0, see
https://www.pivotaltracker.com/n/projects/997278/stories/166970393

UAA clients need to be adapted, therefore this issue

Another example:
https://github.com/cloudfoundry/cf-uaac/issues/50

Locate the UAA token request and Authorization header construction in cf-java-client, then compare it with the RFC 6749 requirement and the referenced AbstractUaaTokenProvider.java example. Done means client credentials are URL-encoded before Base64 encoding and the client works with UAA-RELEASE 74.0.0.