cluster: T4083: Make run dir for heartbeat

[sever-sever]

In 1.4 cluster/heartbeat can't start because there is a lack of
the directory "/run/heartbeat". Create this directory.

https://phabricator.vyos.net/T4083

vyos@r11-roll:~$ show cluster 

  Incomplete command: show cluster

vyos@r11-roll:~$ show cluster status 
=== Status report on primary node r11-roll ===

  Primary r11-roll (this node): Active

  Secondary r12-lts: Down

  Resources [203.0.113.254/24/eth1]:
    Active on primary r11-roll (this node)

vyos@r11-roll:~$ sudo systemctl status heartbeat
● heartbeat.service - Heartbeat High Availability Cluster Communication and Membership
     Loaded: loaded (/lib/systemd/system/heartbeat.service; disabled; vendor preset: enabled)
     Active: active (running) since Mon 2021-12-20 18:57:59 EET; 12min ago
       Docs: man:heartbeat(8)
             http://www.linux-ha.org/wiki/Documentation
   Main PID: 2005 (heartbeat)
      Tasks: 4 (limit: 4695)
     Memory: 8.6M
        CPU: 555ms
     CGroup: /system.slice/heartbeat.service
             ├─2005 heartbeat: master control process
             ├─2028 heartbeat: FIFO reader
             ├─2029 heartbeat: write: mcast eth1
             └─2030 heartbeat: read: mcast eth1