Add nm-dhcp-ib-interfaces element

Currently, NetworkManager can't automatically create default
connection profiles for InfiniBand interfaces.

So, as a workaround, we are adding nm-dhcp-ib-interfaces element to
install NetworkManager-system-connections-infiniband.nmconnection
to NetworkManager to create a wildcard InfiniBand connection profile.

The content of NetworkManager-system-connections-infiniband.nmconnection
is generated by running this command:
`nmcli --offline connection add type infiniband connection.multi-connect multiple`

Closes-Bug: #2016965
Change-Id: Ic972b90e4df9c4aa36cfe3c8631db3e4533045f4

diskimage_builder/elements/nm-dhcp-ib-interfaces/README.rst

@@ -0,0 +1,9 @@
+=====================
+nm-dhcp-ib-interfaces
+=====================
+Add InfiniBand connection profile to run DHCP for InfiniBand interfaces
+
+As it's not implemented yet to create default connection profiles for
+InfiniBand interfaces in NetworkManager, we are providing a wildcard
+InfiniBand connection profile to allow it to run DHCP for InfiniBand
+interfaces.

diskimage_builder/elements/nm-dhcp-ib-interfaces/install.d/50-dhcp-ib-interfaces

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+if [ ${DIB_DEBUG_TRACE:-1} -gt 0 ]; then
+    set -x
+fi
+set -eu
+set -o pipefail
+
+SCRIPTDIR=$(dirname $0)
+
+# Because NetworkManager can't automatically create default connection
+# profiles for InfiniBand interfaces, we are installing
+# NetworkManager-system-connections-infiniband.nmconnection to
+# NetworkManager to create a wildcard InfiniBand connection profile
+install -D -g root -o root -m 0600 ${SCRIPTDIR}/NetworkManager-system-connections-infiniband.nmconnection /etc/NetworkManager/system-connections/infiniband.nmconnection
+exit 0

diskimage_builder/elements/nm-dhcp-ib-interfaces/install.d/NetworkManager-system-connections-infiniband.nmconnection

@@ -0,0 +1,17 @@
+[connection]
+id=infiniband
+type=infiniband
+multi-connect=3
+
+[infiniband]
+transport-mode=datagram
+
+[ipv4]
+method=auto
+
+[ipv6]
+addr-gen-mode=default
+method=auto
+
+[proxy]
+

releasenotes/notes/bug-2016965-f3f35c919081f64c.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    As NetworkManager can't automatically create default connection profiles
+    for InfiniBand interfaces, we are adding nm-dhcp-ib-interfaces element
+    to install NetworkManager-system-connections-infiniband.nmconnection to
+    NetworkManager to create a wildcard InfiniBand connection profile.