Refactor: rewrote Japanese natural language processing code imported from server_editor.py

The logic has not been changed, only renaming, splitting and moving modules on a per-function basis.
Existing code will be left in place for the time being to avoid breaking the training code, which is not subject to refactoring this time.

style_bert_vits2/.editorconfig

@@ -0,0 +1,15 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+indent_size = 4
+indent_style = space
+trim_trailing_whitespace = true
+
+[*.md]
+trim_trailing_whitespace = false
+
+[*.yml]
+indent_size = 2