refactor: add some dev files and black original code

Original server code has been moved to __init__ file, so we can
work on `lnbits` as a package.

.editorconfig

@@ -0,0 +1,14 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.md]
+trim_trailing_whitespace = false
+
+[*.py]
+indent_size = 4
+indent_style = space