Automatic Lambci Management

[NathanTP]

#15 added support for lambci but requires users to manage the backend explicitly (e.g. launching the container with the right lambda). It would be good to push this into SRK (this is how OL works). Some benefits of this:

• Users don't have to fiddle around with docker and potentially make mistakes or get into a weird state.
• We could support installing multiple lambdas. This might require some additional work in terms of building a management layer that does all the stuff AWS does for lambda (e.g. starting new containers for each lambda, potentially re-using containers for multiple requests to the same lambda, etc).
• We could simplify scalable/remote execution by integrating some of the stuff from cffsEval
• If this is done well, we could probably deprecate OL which would be nice (it's proven to be over-complicated and more work than it's worth).