feat: FreeBSD and OpenBSD drivers, read side

FreeBSDDriver (`freebsd`) and OpenBSDDriver (`openbsd`) on a shared
BsdDriver, for the BSD VMs netOrk provisions and BSD hosts added by hand
(NetOrk/netork#798).

- SSH over exec channels (napalm-device-types' run_on_transport): no PTY,
  stdout and stderr apart, real exit codes; run_command()/open_stream()
  are public. Root through `sudo -S` with the password on stdin, or
  `sudo -n` without one.
- Facts: hostname, release and running kernel (freebsd-version / uname),
  hardware from SMBIOS (kenv) or hw.* sysctls, uptime from kern.boottime.
- Interfaces and addresses (ifconfig -a: ether/lladdr, hex netmasks,
  scoped IPv6), routes (netstat -rn, OpenBSD's abbreviated networks
  written out, host/broadcast/loopback entries left out), ARP (FreeBSD's
  sentences, OpenBSD's table), users and groups, processes (lstart read as
  one five-word field), cron jobs (system crontab and the login user's).
- Parsers are pure functions, tested on output recorded from FreeBSD 15.1
  (hand-installed and cloud image) and OpenBSD 7.9 (NetOrk/netork#793),
  with internal addresses replaced by documentation ranges.

tests/fixtures/freebsd-vm/service_l.txt

@@ -0,0 +1,173 @@
+DAEMON
+FILESYSTEMS
+LOGIN
+NETWORKING
+SERVERS
+accounting
+adjkerntz
+apm
+auditd
+auditdistd
+automount
+automountd
+autounmountd
+bgfsck
+blacklistd
+blocklistd
+bluetooth
+bootparams
+bridge
+bsnmpd
+bthidd
+ccd
+cfumass
+cleanvar
+cleartmp
+cron
+ctld
+ddb
+defaultroute
+devd
+devfs
+devmatch
+dhclient
+dmesg
+dnctl
+dumpon
+fsck
+ftp-proxy
+geli
+geli2
+ggated
+gptboot
+growfs
+growfs_fstab
+gssd
+hastd
+hcsecd
+hostapd
+hostid
+hostid_save
+hostname
+inetd
+iovctl
+ip6addrctl
+ipfilter
+ipfs
+ipfw
+ipfw_netflow
+ipmon
+ipnat
+ippool
+ipsec
+iscsictl
+iscsid
+jail
+kadmind
+kdc
+kld
+kldxref
+ldconfig
+linux
+local
+local_unbound
+localpkg
+lockd
+lpd
+mdconfig
+mdconfig2
+mixer
+motd
+mountcritlocal
+mountcritremote
+mountd
+mountlate
+moused
+msconvd
+msgs
+natd
+netif
+netoptions
+netwait
+newsyslog
+nfscbd
+nfsclient
+nfsd
+nfsuserd
+nisdomain
+noshutdown
+nscd
+ntpd
+ntpdate
+nuageinit
+nuageinit_post_net
+nuageinit_user_data_script
+os-release
+pf
+pflog
+pfsync
+power_profile
+powerd
+ppp
+pppoed
+pwcheck
+quota
+random
+rarpd
+rctl
+resolv
+rfcomm_pppd_server
+root
+route6d
+routed
+routing
+rpcbind
+rtadvd
+rtsold
+rwho
+savecore
+sdpd
+securelevel
+sendmail
+serial
+sshd
+statd
+static_arp
+static_ndp
+stf
+swap
+swaplate
+syscons
+sysctl
+sysctl_lastload
+syslogd
+sysvipc
+tlsclntd
+tlsservd
+tmp
+ubthidhci
+ugidfw
+utx
+var
+var_run
+virecover
+virtual_oss
+watchdogd
+wpa_supplicant
+ypbind
+ypldap
+yppasswdd
+ypserv
+ypset
+ypupdated
+ypxfrd
+zfs
+zfsbe
+zfsd
+zfskeys
+zpool
+zpoolreguid
+zpoolupgrade
+zvol
+firstboot_pkg_upgrade
+qemu-guest-agent