New options added to configuration file to reference a public key used
to validate authorization tokens signed by an auth server with
corresponding private key.
Resolves#24
Signed-off-by: Peter Engelbert <pmengelbert@gmail.com>
We are noticing that LDAP connectivity issues and timeouts can affect
authN behavior from client side (which can timeout as well).
Instead, put local authN first so at least we have a reliable authN
method.
But, the caveat is that it is best if the local and LDAP user list
doesn't overlap.
1) github.com/jtblin/go-ldap-client is an abandoned project and not keeping
up with go modules, so pull that code in (single file, BSD license)
2) minor refactor ldap as a result of 1)
3) update go.mod
