fixed some formwatting on the scan page

tools/web_monitor/templates/scan.html

@@ -5,14 +5,14 @@
         <div class="input-group mb-3">
           <span class="input-group-text" id="scan-ip">Subnet</span>
           <input type="text" class="form-control" id="messageText" placeholder="192.168.1.1/24" aria-describedby="scan-ip">
-          <span class="input-group-text"><button>Scan</button></span>
+          <button class="btn btn-primary" onclick="sendMessage()" type="button">Scan</button>
         </div>
     </form>
 </div>
 
 <div class="row w-100">
     <table class="table table-striped table-responsive" style="max-height:300px;">
-        <thead class="table-dark">
+        <thead>
             <tr>
                 <th class="active col-1">
                     <input type="checkbox" class="select-all checkbox" name="select-all" id="selectAllCheckbox"/>