Support HTTPS and related options

[mmccool]

Support (or document them if they already exist) options use HTTPS. This should also support specifying the path to and the names of the certificate and private key files (rather than using fixed names and locations, since they have to be managed by a different subsystem for renewal, eg certbot, and be shared by multiple web services).

There should also be options to support CoAPS, or disable CoAP, or disable HTTP.
It would also be handy to be able to choose the ports used.

[mmccool]

Actually, it would also be useful to support authentication. Not just anyone should be able to access a Thing Directory. I'm looking into resolving both issues using a relay proxy... something like relayd could both act as an HTTPS endpoint and authenticator to control access.

[mmccool]

Likewise I can work around the lack of options to set ports by running the directory service inside a docker container...

[mmccool]

I recently implemented a "proxy wrapper" to get around the lack of HTTPS and authentication. This works, so this is no longer a critical issue, but it is still a desirable capability.