feat: add editorconfig

The following patch adds the file `.editorconfig`. This is the configuration
file of Editorconfig. A general pattern accross IDE's to define basic project
settings like indentation style or indentation size.

Furthermore, the `.gitignore` has been adapted to exclude everything below
`.vscode` excerpt `extensions.json`. The file contains a list of plugin
recommendations, including the new Editorconfig plugin.

Signed-off-by: Markus Pesch <markus.pesch@cryptic.systems>

Author: volker-raschek

.editorconfig

@@ -0,0 +1,15 @@
+# EditorConfig is awesome: https://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = false
+
+[Makefile]
+indent_style = tab

.gitignore

@@ -1,5 +1,7 @@
 # IDE resources
-.vscode
+.vscode/*
+!.vscode/extensions.json
+
 .idea
 .devcontainer/
 

.vscode/extensions.json

@@ -0,0 +1,5 @@
+{
+  "recommendations": [
+    "editorconfig.editorconfig"
+  ]
+}