devtools: add EditorConfig file

EditorConfig is a file format and collection of text editor plugins for
maintaining consistent coding styles between different editors and IDEs.

Initialize the file following the coding rules in
doc/guides/contributing/coding_style.rst,
doc/guides/contributing/documentation.rst and
doc/guides/contributing/patches.rst.

In order for this file to be taken into account (unless they use an
editor with built-in EditorConfig support), developers will have to
install a plugin.

Note: The max_line_length property is only supported by a limited number
of EditorConfig plugins. It will be ignored if unsupported.

Add this new file in MAINTAINERS in the "Developers and Maintainers
Tools" section.

Link: https://editorconfig.org/
Link: https://github.com/editorconfig/editorconfig-emacs
Link: https://github.com/editorconfig/editorconfig-vim
Link: https://github.com/editorconfig/editorconfig/wiki/EditorConfig-Properties#max_line_length

Signed-off-by: Robin Jarry <robin.jarry@6wind.com>

.editorconfig

@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright 2019 6WIND S.A.
+# See https://editorconfig.org/ for syntax reference.
+
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+charset = utf-8
+indent_style = tab
+tab_width = 8
+max_line_length = 80
+
+[*.py]
+indent_style = space
+indent_size = 4
+
+[*.rst]
+indent_style = space
+indent_size = 3
+
+[COMMIT_EDITMSG]
+max_line_length = 72

MAINTAINERS

@@ -104,6 +104,7 @@ F: devtools/load-devel-config
 F: devtools/test-build.sh
 F: devtools/test-meson-builds.sh
 F: license/
+F: .editorconfig
 
 
 Build System