Provide /usr/sbin/installkernel

... (rhbz#2239008).

split-files.py

@@ -123,6 +123,7 @@ for file in files(buildroot):
                        bless-boot|
                        boot-system-token|
                        kernel-install|
+                       installkernel|
                        vconsole|
                        backlight|
                        rfkill|

systemd.spec

@@ -351,6 +351,8 @@ Obsoletes:      systemd < 245.6-1
 Provides:       udev = %{version}
 Provides:       udev%{_isa} = %{version}
 Obsoletes:      udev < 183
+Conflicts:      grubby < 8.40-72
+Conflicts:      sdubby < 1.0-3
 
 # Recommends to replace normal Requires deps for stuff that is dlopen()ed
 # used by dissect, integritysetup, veritysetyp, growfs, repart, cryptenroll, home
@@ -818,6 +820,8 @@ install -m 0755 -D -t %{buildroot}%{_rpmconfigdir}/ %{SOURCE24}
 # https://bugzilla.redhat.com/show_bug.cgi?id=2107754
 install -Dm0644 -t %{buildroot}%{_prefix}/lib/systemd/network/ %{SOURCE25}
 
+ln -s --relative kernel-install %{buildroot}%{_sbindir}/installkernel
+
 %find_lang %{name}
 
 # Split files in build root into rpms. See split-files.py for the