feat(refacto): move everything in internal package

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

internal/generator/katenaryfile/doc.go

@@ -0,0 +1,10 @@
+/*
+Package katenaryfile is a package for reading and writing katenary files.
+
+A katenary file, named "katenary.yml" or "katenary.yaml", is a file where you can define the
+configuration of the conversion avoiding the use of labels in the compose file.
+
+Formely, the file describe the same structure as in labels, and so that can be validated and
+completed by LSP. It also ease the use of katenary.
+*/
+package katenaryfile