Add .editorconfig.json (#58)

Matches abapGit config

.editorconfig

@@ -0,0 +1,22 @@
+# EditorConfig is awesome: https://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+# 1 space indentation for xml files
+[*.xml]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 1
+
+# match the format used by abapGit
+[*.{abap,js,json,html,css}]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_size = 2
+indent_style = space