Add support for multiple domain names

[lightmaster]

Solves issue ameshkov/legoagh#11

TESTING: Tested with both a single and 2 domains when using cloudflare DNS. Should work for all providers that lego supports.

Add parse_domain_names() function to convert a string of comma separated domains (or a single domain) into 2 variables, one containing original domains and one containing wildcard domains.

Change certFileName to use the first value of the DOMAIN_ARRAY to prevent it from breaking saving the cert and key files

Change run_lego() function to use the comma separated strings created in parse_domain_names() function