Extract common options into base class

This is mostly to get consistent defaults for the connection options (host, port, ...) by bringing all programs in on the environment variables added with the client (FDBSQL_HOST, ...).

While touching all of them, also pull out the argument parsing, help printing and URL formatting into the new base class.

Took the route of using the options directly in the other programs as having parallel declarations for them all didn't seem to buy much.