RQD assumes it's hostname is reachable by Cuebot

[KernAttila]

Describe the bug

Hi all ! When launched, RQD sends a host report to Cuebot stating its hostname. But Cuebot cannot reach the RQD machine back (and doesn't know it). In most scenarios it works, but on my setup, machines are able to communicate only via a host nickname, they cannot see the other machines via their local hostname. (I'm using NordVPN meshnet feature to emulate a local network, I guess it should behave the same on other VPN solutions.)

To Reproduce (with all machines on nordvpn meshnet, or any vpn I guess)

1. Clear host list on cuebot
2. Launch RQD -> host appears in cuecommander
3. Lock the machine via cuecommander -> error, cannot communicate
4. Host cannot receive jobs.

Under the hood

1. RQD sends a host report with its hostname.
2. Cuebot saves/updates the host and its stats in the database.
3. RQD continues to send reports saying its alive.
4. Cuebot thinks the machine is available but does not test.

Expected behavior Send a hostname that Cuebot can reach. Suggestion: do a handshake

1. On launch, RQD sends all known hostnames to Cuebot.
2. Cuebot pings back each one and uses the first that responds.
3. Cuebot sends a "gotcha, here's your reachable hostname" to RQD
4. RQD saves that value internally and uses it for its next reports.
5. Cuebot can now reach the RQD host.

Version Number Dev