Rework how EventSelector and InputSvc deal with EventContext and ByteStreamAddress for EventInfo

Now it works like this:
1. Event loop mgr creates an `EventContext` and records it in the event store.
2. Event loop mgr calls `IEvtSelector::createAddress`
3. `TrigEventSelectorByteStream::createAddress` creates a `ByteStreamAddress` for `EventInfo`, which is in line with its name and with the workflow described in the [documentation](/Event/ByteStreamCnvSvc/doc/ByteStream.txt). It also attaches an `EventContext` obtained from the event store to the `ByteStreamAddress`.
4. Event loop mgr calls `IEvtSelector::next` which calls `ByteStreamInputSvc::nextEvent`.
5. `TrigByteStreamInputSvc::nextEvent` gets a new event from `DataCollector::getNext` and passes it on to `ROBDataProviderSvc` using an `EventContext` obtained from the event store.
6. Event loop mgr asks the event store to `loadEventProxies` and then to retrieve an `EventInfo` object. This triggers an automatic conversion from BS (`RawEvent`) to `EventInfo`.