[Code formatting: Change indentation style to space](https://github.com/clicon/clixon/issues/379)

* Applies to all c/h/y/l/sh files and .editorconfig

test/test_netconf_whitespace.sh

@@ -50,7 +50,7 @@ module whitespace{
           type string;
         }
         container b{
-	  presence true;
+           presence true;
         }
      }
   }
@@ -67,7 +67,7 @@ if [ $BE -ne 0 ]; then
     new "kill old backend"
     sudo clixon_backend -zf $cfg -s startup
     if [ $? -ne 0 ]; then
-	err
+        err
    fi
     new "start backend -s startup -f $cfg"
     start_backend -s startup -f $cfg 
@@ -143,7 +143,7 @@ if [ $BE -ne 0 ]; then
     # Check if premature kill
     pid=$(pgrep -u root -f clixon_backend)
     if [ -z "$pid" ]; then
-	err "backend already dead"
+        err "backend already dead"
     fi
     # kill backend
     stop_backend -f $cfg