Fix Preseed late_command

[xeluior]

This PR fixes a number of small bugs preventing the genisys-firstboot.service from running.

1. Adds an alias for the genisys host as genisys.internal in DNSMasq so that SSL can use a hostname
2. Updates the entrypoint script for using the new hostname and fixing some commands
3. Adds a block to chown the SSL cert to the server user if it was generated by the install subcommand (which expects to be ran as root)
4. Concatenates the SSL pubkey, SSH pubkey, and firstboot FTP logic into a single command string since preseed can only accept one value for the late_command directive
5. When dropping server priviledges, take up all groups of the server user, in addition to the specified group, to allow file acls on auxiliary files (like the config file) to function as expected
6. Add the "inventory" test case to the VirtualBox testing scripts