Easyrsa version range

[jan-win1993]

Pull Request (PR) description

This pull request addresses 3 problems:

1. Since easy-rsa version 3.0.3 the name of the easy-rsa configuration file did change from "openssl-1.0.cnf" to "openssl-easyrsa.cnf"
   The following is a link to the corresponding commit:
   OpenVPN/easy-rsa@e8cd6c9.
   To tackle that problem I would like to introduce easy-rsa version ranges and change the file name if a version above 3.0.3 is used.
2. I did also run into a problem with the "./easy-rsa build-server-full" command which opened an input prompt, which could be suppressed using the "--batch" option
3. The whole openssl output with text gets copied to the client configuration file. I've added a exec resource which runs the "openssl" command with the "-noout" option to suppress the unnecessary text output.