units/getty@.service: use [Install]Alias= instead of static alias

In Fedora, kmsconvt@.service is starting to be used instead of getty@.service
to have nicer font handling. This means that we need the autovt@.service alias
point to the new unit. So far the alias was done through a static symlink
because there was little reason to change it. Let's use [Install] instead so
the decision which implementation to use can be made after installation.

https://bugzilla.redhat.com/show_bug.cgi?id=2429626
https://fedoraproject.org/wiki/Changes/UseKmsconVTConsole

units/getty@.service.in

@@ -47,6 +47,7 @@ KillMode=process
 {% endif %}
 IgnoreSIGPIPE=no
 SendSIGHUP=yes
+
 ImportCredential=tty.virtual.%I.agetty.*:agetty.
 ImportCredential=tty.virtual.%I.login.*:login.
 ImportCredential=agetty.*
@@ -58,5 +59,7 @@ ImportCredential=shell.*
 UnsetEnvironment=LANG LANGUAGE LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT LC_IDENTIFICATION
 
 [Install]
+Alias=autovt@.service
+
 WantedBy=getty.target
 DefaultInstance=tty1

units/meson.build

@@ -45,7 +45,6 @@ units = [
         },
         {
           'file' : 'getty@.service.in',
-          'symlinks' : ['autovt@.service'],
         },
         {
           'file' : 'graphical.target',