Add an editorconfig file

.editorconfig

@@ -0,0 +1,17 @@
+# https://editorconfig.org/
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+
+[{*.{c,cpp,h,h.in,cu,cl,hip,f90,java,sh,sh.in,mk,gp},Makefile,Makefile.*}]
+trim_trailing_whitespace = true
+indent_style = tab
+indent_size = 8
+
+[*.{py,jl}]
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 4