What: add monkit.Task to a bunch of functions that are missing it
Why: this will significantly help our instrumentation, data collection, and tracing about what's going on in the network
* set up voucher service skeleton, basic test
* add VetNode db method
* basic test for VetNode
* encode and sign voucher functions
* fill out and sign vouchers
* test pass/fail voucher request
* match EncodeVoucher to other Encode functions
