client: Add basic support for projects
client: Add basic support for projects

This allows passing the project name as a string to Client and have it
automatically added to all URLs.

Blackened by @d0ugal for easier merging.

Signed-off-by: Stéphane Graber <089afc6d81f66f1168a9849e15660feae286e024@ubuntu.com>
Signed-off-by: Dougal Matthews <8f24f2c0fd825cfb6716a36822888c4a01678c88@dougalmatthews.com>

lxc/pylxd,lxc/pylxd