packaging: move api from /api to /ovirt-engine/api

part of the effort to make the ovirt-engine application well behaved
application we would like to stop abusing root context of the web
server.

for backward compatibility /api/* will be forwarded into
/ovirt-engine/api/* without redirect.

the uris that will be returned in the response will reference to the
/ovirt-engine/api namespace.

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=961677
Change-Id: I2ab8396359db608bb2eaae366f31b92034fa4413
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>