HPCC-11157 Allow install-cluster run concurrently

1) Original install-cluster.sh is divided to two files:
  1.1) install-cluster.sh:
       1.1.1 ) top level script.
       1.1.2 ) get admin user passwords.
       1.1.3 ) create package for remote install
       1.1.4 ) excute install-hpcc.exp through cluster_script.py if python 2.6+ detected.
               It allows mulitple instances run simultanously. If no suitable python
               installed install-hpcc.exp will execute sequentially for each ip.

  1.2) install-hpcc.exp
       1.2.1) run on each host to install and configure HPCC.
       1.2.2) check connection logic is added. If it fails no furhter action will be
              applied on the host.
       1.2.3) Add handling ssh/scp connection without password which is normal in cloud
              environment.
2) The original script only install if hpcc user doesn't exists on the host. The fix
   lefts the restriction to allow installation always go through. If HPCC exists and the
   image version is newer it will update it.

3) Log file is at /var/log/HPCCSystesm/cluster/XX_install-hpcc_yyyymmdd_HHMMSS.log
    For concurrent exection XX is cc. If run sequentially it is se
Merge pull request #6018 from xwang2713/HPCC-11157-install-cluster

HPCC-11157 Allow install-cluster run concurrently

Reviewed-By: Chris Lo <christopher.lo@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>