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

.drone.yml

@@ -37,6 +37,7 @@ steps:
     path: /go
   commands:
   - CGO_ENABLED=0 GTS_DB_TYPE="sqlite" GTS_DB_ADDRESS=":memory:" go test ./...
+  - CGO_ENABLED=0 ./test/cliparsing.sh
   when:
     event:
       include:
@@ -115,6 +116,6 @@ trigger:
 
 ---
 kind: signature
-hmac: 8a363baa3c7b5e581bd101a7774422042833b7d297faf5d93c9156cf54a31124
+hmac: 3c989818a1940fc572110fa35b76b6ea82e9c45a3b1074e3af6328550f12674c
 
 ...