Implement simple single planner

[hannahhoward]

Goals

Implement an initial single planner, prepping to implement the larger planner

Implementation

• implement simple single planner with a min target score and a max wait time -- will receive results until a value is over target score or max wait time is reached, and then return a plan with a single request for the best result
• move filecoin v1 out of root dir
• refactor and simplify policy/interpreter interface
• continue to wonder if this can be done in a protocol neutral way, or we should simply have each interpreter return a plan. Then the question becomes choosing between interpreters? Not sure!

[willscott]

The plan setup looks fine.

[willscott]

do we have to call this filecoin records, rather than data-transfer/graphsync? which is the protocol spoken here?