Fix missing header

Was relying on QRunnable being included in another header
Don’t treat EAGAIN or EWOULDBLOCK as error, instead retry up to 3 times

It would probably be more elegant to fix MSocketDevice::readData instead, but as it’s the only location using the MSocketDevice that way, it will be fine for now

Fixes #11517
Make mythlogserver build and use conditional.

When disabled, provide equivalent functionalities; each application running an extra logging thread that will handle syslog, file or db logging.
Remove the dependency on zeromq and nzmqt.

Default is mythlogserver daemon enabled
Properly propagate quiet log option

—quiet was being propagated when not set. Test was reverse or documentation is wrong
Add —nologserver option

This will limit all logs to console, disabling file, db and syslog.
If enabled, mythlogserver will never be started; or if built without mythlogserver, two extra threads won’t be created

Ref #11230 and #11784: not a fix, but allow to bypass the issue
Update ABI following addition to —nologserver