feature: Formatting for namespace

namespaces are an important entity in most places.
So let's put the braces on their own lines to improve the
boundary markings. Much like with class's.

Author: ChristianTackeGSI

.clang-format

@@ -21,6 +21,7 @@ BraceWrapping:
   AfterClass: true
   AfterEnum: true
   AfterFunction: true
+  AfterNamespace: true
   AfterStruct: true
   SplitEmptyFunction: false
   SplitEmptyRecord: false