Add Package Config :

- major dependancies are :
  - golib/context config
  - golib/viper
- interface config extend :
  - golib/context config interface
  - component list
- interface component list :
  this interface implement all function to manage a collection of component. All component are registred with they config key.
  A component must implement basic function like start, stop, reload, defaultConfig...
  The main config json is set by calling all component config with the config key attached
  Each component have some status status like isStarted, isRunning, ...
  Each component must also declare his dependencies with other component. As that when start or reload is called,
  the component is sure that dependencies are still started or reloaded.
- They are 4 component for now : log, tls, headers and http server
- The config package will start a new context / cancelfunc on init to be sure to stop cleanly all component and process

Add Package Viper :
- this package is an helper to the config package with the spf13 viper lib
- this package can watch any change of a config file or can be connected to a remote config cluster like ETCD

Add Package Cobra :
- this package is an helper to make a CLI with flag / command
- this package is based on spf13 cobra has all method to be connected to viper golib

errors/modules.go

@@ -31,26 +31,28 @@ const (
 	MinPkgArtifact    = 200
 	MinPkgCertificate = 300
 	MinPkgCluster     = 400
-	MinPkgConsole     = 500
-	MinPkgCrypt       = 600
-	MinPkgHttpCli     = 700
-	MinPkgHttpServer  = 800
-	MinPkgIOUtils     = 900
-	MinPkgLDAP        = 1000
-	MinPkgLogger      = 1100
-	MinPkgMail        = 1200
-	MinPkgMailer      = 1300
-	MinPkgMailPooler  = 1400
-	MinPkgNetwork     = 1500
-	MinPkgNats        = 1600
-	MinPkgNutsDB      = 1700
-	MinPkgOAuth       = 1800
-	MinPkgAws         = 1900
-	MinPkgRouter      = 2000
-	MinPkgSemaphore   = 2100
-	MinPkgSMTP        = 2200
-	MinPkgStatic      = 2300
-	MinPkgVersion     = 2400
+	MinPkgConfig      = 500
+	MinPkgConsole     = 600
+	MinPkgCrypt       = 700
+	MinPkgHttpCli     = 800
+	MinPkgHttpServer  = 900
+	MinPkgIOUtils     = 1000
+	MinPkgLDAP        = 1100
+	MinPkgLogger      = 1200
+	MinPkgMail        = 1300
+	MinPkgMailer      = 1400
+	MinPkgMailPooler  = 1500
+	MinPkgNetwork     = 1600
+	MinPkgNats        = 1700
+	MinPkgNutsDB      = 1800
+	MinPkgOAuth       = 1900
+	MinPkgAws         = 2000
+	MinPkgRouter      = 2100
+	MinPkgSemaphore   = 2200
+	MinPkgSMTP        = 2300
+	MinPkgStatic      = 2400
+	MinPkgVersion     = 2500
+	MinPkgViper       = 2600
 
 	MinAvailable = 4000