Add .editorconfig

Add .editorconfig file containing the editor configurations for common
source files.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>

Author: stephanosio

.editorconfig

@@ -0,0 +1,31 @@
+# EditorConfig: https://editorconfig.org/
+
+# top-most EditorConfig file
+root = true
+
+# All (Defaults)
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+max_line_length = 100
+
+# Git commit messages
+[COMMIT_EDITMSG]
+max_line_length = 75
+
+# Dockerfile
+[Dockerfile*]
+indent_style = tab
+indent_size = 8
+
+# Shell Script
+[*.sh]
+indent_style = space
+indent_size = 2
+
+# YAML
+[*.{yml,yaml}]
+indent_style = space
+indent_size = 2