Introduce command 'write' - Write support files

This allows creating all support files.

Usage: 'easyrsa write <type> <DIR>'
* <type> must be specified.
* <DIR> is optional. If specified then files are created.
        Otherwise, data is sent to stdout.

Types:
* ssl-cnf  - Write openssl-easyrsa.cnf file.
* COMMON|ca|server|serverCleint|client|codeSigning|email|kdc
           - Write x509-type <type> file.
* lecacy   - Write ALL files above to <DIR>.
             Default <DIR> is EASYRSA_PKI or EASYRSA.
             Will create <DIR>/x509-types direcotry.
* safe-ssl - Expand Easy-RSA SSL config for LibreSSL.
* vars     - Write vars.example file.

Replaces command 'make-safe-ssl' and 'make-vars'.

Signed-off-by: Richard T Bonhomme <[email protected]>