Build a simple API that given the asset tag (Serial Number in Netbox terminology) of the host returns the boot options
* lookup the host on Netbox via the Serial Number and generate its FQDN
* query the DNS for the network config based on FQDN
* if the hostname is present in a short-lived cache generated by the reimage script, return the iPXE commands, including hostname, network config, and URL of the OS, allowing to override the default OS based on the parameters in the cache.
* Hosts will reimain configured to boot from local disk by default for now, the reimage script will continue to force PXE. With the added benefit that if a host remains with the force PXE it will not go into d-i on reboot.