Patch sent to upstream: https://github.com/nmstate/nmstate/pull/2315

Introducing these two DHCP options:
 * `dhcp-send-hostname`: true of false, whether DHCP request should
   contain hostname/FQDN option. Default is true.
 * `dhcp-custom-hostname`: String. Customer hostname/FQDN in DHCP
   request.

For DHCPv4, if the hostname is FQDN, the 'Fully Qualified Domain Name
(FQDN)' option(81) defined in RFC 4702 will be used.
If the hostname is not FQDN, the 'Host Name' option(12) defined in RFC
2132 will be used.

For DHCPv6, custom string to override hostname used for DHCP request in
`Fully Qualified Domain Name (FQDN)` option(29) defined in RFC 4704 as
RFC 4704 allows empty domain name.

Example YAML:

```yml
---
interfaces:
  - name: eth1
    type: ethernet
    state: up
    mtu: 1500
    ipv4:
      dhcp: true
      dhcp-client-id: iaid+duid
      enabled: true
      dhcp-send-hostname: true
      dhcp-custom-hostname: c9.example.org
    ipv6:
      dhcp: true
      autoconf: true
      enabled: true
      dhcp-send-hostname: true
      dhcp-custom-hostname: c9.example.net
```

Do we cover the fcos examples with this ?

https://docs.fedoraproject.org/en-US/fedora-coreos/sysconfig-network-configuration/#_configuring_a_static_ip

Yes. For `ip=10.10.10.10::10.10.10.1:255.255.255.0:myhostname:ens2:none:8.8.8.8`, nmstate YAML is:


```yml
---
hostname:
  config: myhostname
dns-resolver:
  config:
    server:
    - 8.8.8.8
routes:
  config:
  - destination: 0.0.0.0/0
    next-hop-address: 10.10.10.1
    next-hop-interface: ens2
interfaces:
  - name: ens2
    type: ethernet
    state: up
    ipv4:
      address:
      - ip: 10.10.10.1
        prefix-length: 24
      dhcp: false
      enabled: true
    ipv6:
      enabled: false
```

Verified with:
nmstate-2.2.10-3.el9.x86_64
nispor-1.2.10-1.el9.x86_64
NetworkManager-1.43.8-1.el9.x86_64
DISTRO=RHEL-9.3.0-updates-20230520.44

[17:26:27@dell-per730-20 ~]0# nms set dhcp-send.yaml 
/tmp/nmstatelog/2023-05-21-17:27:21-038936344.log
dns-resolver: {}
route-rules: {}
routes: {}
interfaces:
- name: veth0
  type: ethernet
  state: up
  mtu: 1500
  ipv4:
    enabled: true
    dhcp: true
    dhcp-client-id: iaid+duid
    dhcp-send-hostname: true
    dhcp-custom-hostname: c9.example.org
  ipv6:
    enabled: true
    dhcp: true
    autoconf: true
    dhcp-send-hostname: true
    dhcp-custom-hostname: c9.example.net
  veth:
    peer: veth0_p
ovs-db: {}

/tmp/nmstatelog/2023-05-21-17:27:21-038936344.0.log nmstatectl set dhcp-send.yaml return 0
[17:27:23@dell-per730-20 ~]0# nmcli con show veth0 | grep -i dhcp
ipv4.dhcp-client-id:                    duid
ipv4.dhcp-iaid:                         --
ipv4.dhcp-timeout:                      2147483647 (infinity)
ipv4.dhcp-send-hostname:                yes
ipv4.dhcp-hostname:                     --
ipv4.dhcp-fqdn:                         c9.example.org
ipv4.dhcp-hostname-flags:               0x0 (none)
ipv4.dhcp-vendor-class-identifier:      --
ipv4.dhcp-reject-servers:               --
ipv6.dhcp-pd-hint:                      --
ipv6.dhcp-duid:                         ll
ipv6.dhcp-iaid:                         mac
ipv6.dhcp-timeout:                      2147483647 (infinity)
ipv6.dhcp-send-hostname:                yes
ipv6.dhcp-hostname:                     c9.example.net
ipv6.dhcp-hostname-flags:               0x0 (none)

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (nmstate bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2023:6323