ocserv should not depend on autogen

In order to support multiple vhosts support in ocserv we need to have a configuration format which supports sections such as:

[vhost:test.example.com]
setting1 = value1

However, autogen doesn't provide that capability unless we switch to XML configuration which we shouldn't for backwards compatibility (and a dislike of xml for configuration).

We should provide something simpler such as:

• https://github.com/benhoyt/inih