chg: [htaccess] lock the backreference escaping purely to spaces - if we need more we can change it in the future

app/.htaccess

@@ -1,5 +1,5 @@
 <IfModule mod_rewrite.c>
     RewriteEngine on
-    RewriteRule    ^$    webroot/    [B,L]
-    RewriteRule    (.*) webroot/$1    [B,L]
+    RewriteRule    ^$    webroot/    "[B= ,L]"
+    RewriteRule    (.*) webroot/$1    "[B= ,L]"
 </IfModule>

app/webroot/.htaccess

@@ -2,7 +2,7 @@
     RewriteEngine On
     RewriteCond %{REQUEST_FILENAME} !-d
     RewriteCond %{REQUEST_FILENAME} !-f
-    RewriteRule ^(.*)$ index.php?/$1 [QSA,L,B]
+    RewriteRule ^(.*)$ index.php?/$1 "[QSA,L,B= ]"
 
     # Adds AUTH support to Rest Plugin:
     RewriteRule .* - [env=HTTP_AUTHORIZATION:%{HTTP:Authorization},last]