add openModal function for each button and adjust Modal header style

src/client/js/components/PageAccessoriesModal.jsx

@@ -19,7 +19,7 @@ const PageAccessoriesModal = (props) => {
       toggle={props.onClose}
       className="grw-create-page"
     >
-      <ModalHeader tag="h4" className="bg-primary text-light">
+      <ModalHeader tag="h4">
         { t('TopOfTableContentsModal') }
       </ModalHeader>
       <ModalBody>

src/client/js/components/TopOfTableContents.jsx

@@ -44,15 +44,15 @@ const TopOfTableContents = (props) => {
           <PageList />
         </button>
 
-        <button type="button" className="bg-transparent border-0">
-          <TimeLine onClick={renderModal} />
+        <button type="button" className="bg-transparent border-0" onClick={openPageAccessoriesModal}>
+          <TimeLine />
         </button>
 
-        <button type="button" className="bg-transparent border-0">
+        <button type="button" className="bg-transparent border-0" onClick={openPageAccessoriesModal}>
           <RecentChanges />
         </button>
 
-        <button type="button" className="bg-transparent border-0">
+        <button type="button" className="bg-transparent border-0" onClick={openPageAccessoriesModal}>
           <Attachment />
         </button>
         {/* [TODO: setting Footprints' icon by GW-3308] */}