feat(refacto): move everything in internal package

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

doc/docs/packages/internal/generator/extrafiles.md

@@ -0,0 +1,28 @@
+<!-- Code generated by gomarkdoc. DO NOT EDIT -->
+
+# extrafiles
+
+```go
+import "github.com/katenary/katenary/internal/generator/extrafiles"
+```
+
+Package extrafiles provides function to generate the Chart files that are not objects. Like README.md and notes.txt...
+
+## func [NotesFile](<https://github.com/katenary/katenary/blob/master/internal/generator/extrafiles/notes.go#L13>)
+
+```go
+func NotesFile(services []string) string
+```
+
+NotesFile returns the content of the note.txt file.
+
+<a name="ReadMeFile"></a>
+## func [ReadMeFile](<https://github.com/katenary/katenary/blob/master/internal/generator/extrafiles/readme.go#L46>)
+
+```go
+func ReadMeFile(charname, description string, values map[string]any) string
+```
+
+ReadMeFile returns the content of the README.md file.
+
+Generated by [gomarkdoc](<https://github.com/princjef/gomarkdoc>)