Implement Cobra CLI tooling, Viper config tooling (#336)

* start pulling out + replacing urfave and config

* replace many many instances of config

* move more stuff => viper

* properly remove urfave

* move some flags to root command

* add testrig commands to root

* alias config file keys

* start adding cli parsing tests

* reorder viper init

* remove config path alias

* fmt

* change config file keys to non-nested

* we're more or less in business now

* tidy up the common func

* go fmt

* get tests passing again

* add note about the cliparsing tests

* reorganize

* update docs with changes

* structure cmd dir better

* rename + move some files around

* fix dangling comma

testrig/router.go

@@ -27,7 +27,7 @@ import (
 
 // NewTestRouter returns a Router suitable for testing
 func NewTestRouter(db db.DB) router.Router {
-	r, err := router.New(context.Background(), NewTestConfig(), db)
+	r, err := router.New(context.Background(), db)
 	if err != nil {
 		panic(err)
 	}