feat(refacto): move everything in internal package

This allows to install katenary with `go install` and to clean up the
project folder.

internal/generator/extrafiles/notes.tpl

@@ -0,0 +1,39 @@
+Thanks to have installed {{ .Chart.Name }} {{ .Chart.Version }} as {{ .Release.Name }} ({{.Chart.AppVersion }}).
+
+# Get release information
+
+To learn more about the release, try:
+
+  $ helm -n {{ .Release.Namespace }} status {{ .Release.Name }}
+  $ helm -n {{ .Release.Namespace }} get values {{ .Release.Name }}
+  $ helm -n {{ .Release.Namespace }} get all {{ .Release.Name }}
+
+# To delete the release
+
+Use helm uninstall command to delete the release. 
+
+  $ helm -n {{ .Release.Namespace }} uninstall {{ .Release.Name }}
+
+Note that some resources may still be in use after a release is deleted. For exemple, PersistentVolumeClaims are not deleted by default for some storage classes or if some annotations are set.
+
+# More information
+
+You can see this notes again by running:
+
+  $ helm -n {{ .Release.Namespace }} get notes {{ .Release.Name }}
+
+{{- $count := 0 -}}
+{{- $listOfURL := "" -}}
+{{* DO NOT REMOVE, replaced by notes.go: ingress_list *}}
+{{- if gt $count 0 }}
+
+# List of activated ingresses URL:
+{{ $listOfURL }}
+
+You can get these urls with kubectl:
+
+    kubeclt get ingress -n {{ .Release.Namespace }}
+
+{{- end }}
+
+Thanks for using Helm!