fix r509 binary to use changed selfsign method
update selfsign to add basicConstraints defaulting to CA:TRUE if no

extensions array is passed
change engine keys to symbols for consistency with the rest
update yaml files for tests/use #to_yaml output
major documentation updates & more

added validation of input for extension creation
allow passing of R509::ASN1::GeneralNames objects for
-cdp_location
-ocsp_location
-ca_issuers_location
in R509::Config::CertProfile