Add a security framework for authenticating connections - we will add LDAP, Kerberos, and Keystone support in the next month. For now, just put a placeholder "basic" module that does the minimum.

Wire the security check into ORTE's OOB handshake, and add a "version" check to ensure that both ends are from the same ORTE version. If not, report the mismatch and refuse the connection

Fixes #4171

cmr=v1.7.5:reviewer=jsquyres:subject=Add a security framework for authenticating connections