[OSGi] Proxy Configuration PID changed between 4.x and 5.x branches

The PID for the OSGi Proxy Configuration was changed between 4.x and 5.x.

As the PID is just an opaque string, there is no need to break existing proxy configurations with the update from 4.x to 5.x. Hence I suggest to revert the PID to its previous value.

Also, to stay consistent in the naming, I would change/revert the other PIDs to start with "org.apache.http."

WDYT, simone.tripodi?