Refactor traefik with package

Split a bit traefik into package. The idea behind this refactor is to
start move inter-dependencies away and do some DRY or SRP.

- Adds a `provider` package, with providers except `web.go`
- Adds a `types` package with common struct.
- Move `gen.go` to an `autogen` package

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

provider/boltdb.go

@@ -0,0 +1,16 @@
+package provider
+
+import "github.com/emilevauge/traefik/types"
+
+type BoltDbProvider struct {
+	Watch      bool
+	Endpoint   string
+	Prefix     string
+	Filename   string
+	KvProvider *KvProvider
+}
+
+func (provider *BoltDbProvider) Provide(configurationChan chan<- types.ConfigMessage) error {
+	provider.KvProvider = NewBoltDbProvider(provider)
+	return provider.KvProvider.provide(configurationChan)
+}