Fixes#250, replacing cookies with auth-bearer tokens. This is done using fernet with randomised keys each startup. The reason for this is that in the future the size of the auth token may exceed cookie limits, so we must be able to understand and process auth bearer. Additionaly, this lets us store the tokens for say the kanidm cli as reqwest today can't persist a cookie jar.
Fixes#101, concurrent caching of IDL and Entries. This yields a 10% improvement for test case execution, and 35% for tests run under --release mode. A lot of code around the code base was needed to be touched due to the extra need for mut in some operations and some lifetimes, but the majority of the work was in idl_arc_sqlite.rs, which has the cache layer. There are many performance gains yet to see, but most of those will come through improvement of the concread ARC and it's related BTree implementation.
Implements #134 Client Builder Pattern. This makes it much easier to build a client by making the configuration of the client lib follow a builder pattern. The error management needs a lot of work still, but for now it's rough and it works.
Implemnt SSH public key management
This implements ssh public key distribution for kanidm, enforcing that
valid ssh public keys are placed into the ssh_publickey attribute, adds
management tools so that accounts can self-service manage their keys,
and finally adds an authorized keys command helper suitable for
sshd_config to utilise.
