All of our install/admin scripts had a try/except block calling the
main function and handling common exceptions. These were copy-pasted
from each other and modified to various levels of sophistication.
This refactors them out of installers to a single function, which
includes a final pass/fail message for all of the scripts.

Non-install scripts that set up the same log handler levels for
stderr and log file are not changed, as it's not possible to log
to only the logfile without changing the logger configuration.

https://fedorahosted.org/freeipa/ticket/2071

When getpass.getpass() function is interrupted via CTRL+D, EOFError
exception is thrown. Most of the install tools are not prepared for
this event and crash with this exception. Make sure that it is
handled properly and nice error message is printed.

https://fedorahosted.org/freeipa/ticket/1916

Install tools may fail with unexpected error when IPA server is not
installed on a system. Improve user experience by implementing
a check to affected tools.

https://fedorahosted.org/freeipa/ticket/1327
https://fedorahosted.org/freeipa/ticket/1347

The patch also corrects exception handling in some of the tools.

Fix #874

The changes include:
 * Change license blobs in source files to mention GPLv3+ not GPLv2 only
 * Add GPLv3+ license text
 * Package COPYING not LICENSE as the license blobs (even the old ones)
   mention COPYING specifically, it is also more common, I think

 https://fedorahosted.org/freeipa/ticket/239

This allows us to have the CA ready to serve out certs for any operation even
before the dsinstance is created. The CA is independent of the dsinstance
anyway.

Also fixes: https://fedorahosted.org/freeipa/ticket/544

Instead of print and return, use sys.exit() to quit scripts with an
error message and a non zero return code.

https://fedorahosted.org/freeipa/ticket/425

Also use the realm name as nickname for the CA certificate