schleuder-api-daemon: please don't bind the use of API keys to TLS
until #155 is resolved, API keys can be useful to constrain access to the schleduer-api-daemon
even if it's running on the loopback.
if the docs are correct and API keys will not be accepted on the loopback, and TLS is disabled by default on the loopback, that's a wide-open control mechanism.
I've had to enable TLS on the loopback interface in order to require the use of API keys, and TLS on the loopback seems a little silly.
If schleuder-api-daemon is listening on an internet socket, then the choice of TLS-or-not should depend strictly on whether the interface is a loopback interface: no TLS for loopback and mandatory TLS for non-loopback.
The use of API keys should be mandatory for all connections on an internet socket, regardless of TLS.
(if #155 is resolved, then you can still avoid the hassle of configuring API keys on the local machine by relying on filesystem permissions and SO_PEERCRED
instead)