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

vendor/github.com/spf13/viper/.golangci.yml

@@ -0,0 +1,93 @@
+run:
+    timeout: 5m
+
+linters-settings:
+    gci:
+        local-prefixes: github.com/spf13/viper
+    golint:
+        min-confidence: 0
+    goimports:
+        local-prefixes: github.com/spf13/viper
+
+linters:
+    disable-all: true
+    enable:
+        - bodyclose
+        - deadcode
+        - dogsled
+        - dupl
+        - durationcheck
+        - exhaustive
+        - exportloopref
+        - gci
+        - goconst
+        - gofmt
+        - gofumpt
+        - goimports
+        - gomoddirectives
+        - goprintffuncname
+        - govet
+        - importas
+        - ineffassign
+        - makezero
+        - misspell
+        - nakedret
+        - nilerr
+        - noctx
+        - nolintlint
+        - prealloc
+        - predeclared
+        - revive
+        - rowserrcheck
+        - sqlclosecheck
+        - staticcheck
+        - structcheck
+        - stylecheck
+        - tparallel
+        - typecheck
+        - unconvert
+        - unparam
+        - unused
+        - varcheck
+        - wastedassign
+        - whitespace
+
+        # fixme
+        # - cyclop
+        # - errcheck
+        # - errorlint
+        # - exhaustivestruct
+        # - forbidigo
+        # - forcetypeassert
+        # - gochecknoglobals
+        # - gochecknoinits
+        # - gocognit
+        # - gocritic
+        # - gocyclo
+        # - godot
+        # - gosec
+        # - gosimple
+        # - ifshort
+        # - lll
+        # - nlreturn
+        # - paralleltest
+        # - scopelint
+        # - thelper
+        # - wrapcheck
+
+        # unused
+        # - depguard
+        # - goheader
+        # - gomodguard
+
+        # don't enable:
+        # - asciicheck
+        # - funlen
+        # - godox
+        # - goerr113
+        # - gomnd
+        # - interfacer
+        # - maligned
+        # - nestif
+        # - testpackage
+        # - wsl