HPCC-9415 New epoll implementation with common base class

Signed-off-by: Mark Kelly <mark.kelly@lexisnexis.com>
HPCC-9415 Disable by default for now

Signed-off-by: Mark Kelly <mark.kelly@lexisnexis.com>
HPCC-9415 Datest new code for createRemoteFile testing

Signed-off-by: Mark Kelly <mark.kelly@lexisnexis.com>