[x] make sure to assign proper serverHost in the wopi token db entry on both servers (we need to keep track on both servers that the editing is happening and where the user got redirected)
[x] make sure to assign proper access_token in the wopi token db entry on both servers (in case remotes need to exchange some further information between each other)
[x] extend "federated handshake" to allow to retrieve editor uid and other wopi session details from remote
[x] adjust tests
[x] make sure to use new major version for the release @jnweiger
implements https://github.com/owncloud/richdocuments/issues/381