Implement a new generic proxy for RDMA devices that don't require a plugin.

We create a new generic plugin for rdmaproxy. Such a plugin is needed because
in iRDMA, CQ and QPs are actually implemented as MRs, which already get handled
correctly by rdmaproxy core. Furthermore, these MRs are indexed by virtual
addresses, so a guest VA is never dereferenced in kernel space for CQ/QP
operations. Therefore a specialized driver plugin to rdmaproxy is not required.
Since we still have to register a driver-plugin for each device at registration
time, we instead register a generic plugin which does nothing. We only register
the generic plugin for an allow-list of drivers such as idpf or ice, which are
all managed by the irdma subsystem.