Implement Digest Authentication

[billmeek]

In 0.28-pre, users can activate basic and digest authentication with:

    curl --digest --user admin:mythtv --data Key=HTTP/Protected/Urls --data Value=/ BE:6544/Myth/PutSetting

Where the '/' protects everything, including all Services API
services. '/Myth;/Content' would only protect 2 services.

Probably needs an upstream GUI to change the setting before
implementing the feature in the app.

curl --digest --user admin:mythtv BE:6544/Myth/GetHostName works

[dmfrey]

For this, is there instructions to enable this on the backend anywhere? I'm hesitant for basic and digest authentication. Ideally, I would like to see an OAuth service added to the backend. You are allowing the app to act on behalf of the user on the backend. Plus it's more secure and can be backed by another trusted provider if desired.

[billmeek]

No instructions, or even GUI. I've got some new methods
coded up for the backend to add/change/delete passwords.
The next step would be new endpoints to use the new code.

I can't find any mention of OAuth in the existing code. I know
we discussed this briefly at dinner in Indy. As I recall, there
isn't any Digest authentication in Spring, only Basic.

I've been testing the backend with both Basic and Digest
(mostly Digest.)