Change table layout to CSS base table structure

- For the editor in the home view, a layout table is used, and it includes the use of IDs. This can
potentially lead to issues with the interpretation of content by assistive technologies
- Layout tables are
meant to structure the layout of a page and should not contain structural markup like th , caption ,
summary , headers , or id.

Solution:
- replace `td` and 'table' tag with `div`
- make some changes on css to be consistent with our prev design
Signed-off-by: Darshan-upadhyay1110 <darshan.upadhyay@collabora.com>
Change-Id: I136cd8d51b2e5035c6ef4292f759f49519e5bd61

browser/css/cool.css

@@ -325,6 +325,8 @@ nav.spreadsheet-color-indicator ~ #sidebar-dock-wrapper {
 	z-index: 11 !important;
 	border-bottom: 1px solid var(--color-border);
 	background-color: var(--color-background-lighter);
+	display: flex;
+	flex-direction: column;
 }
 #toolbar-wrapper:not(.mobile) {
 	padding: 3px 0;

browser/html/cool.html.m4

@@ -201,21 +201,17 @@ m4_ifelse(MOBILEAPP,[true],
       </div>
      </nav>
 
-     <table id="toolbar-wrapper">
-     <tr>
-       <td id="toolbar-logo"></td>
-       <td id="toolbar-mobile-back" class="editmode-off"></td>
-       <td id="toolbar-up"></td>
-       <td id="toolbar-hamburger">
+     <div id="toolbar-wrapper">
+       <div id="toolbar-logo"></div>
+       <div id="toolbar-mobile-back" class="editmode-off"></div>
+       <div id="toolbar-up"></div>
+       <div id="toolbar-hamburger">
          <label class="main-menu-btn" for="main-menu-state">
            <span class="main-menu-btn-icon" id="main-menu-btn-icon"></span>
          </label>
-       </td>
-     </tr>
-     <tr>
-       <td colspan="4" id="formulabar" style="display: none"></td>
-     </tr>
-    </table>
+       </div>
+       <div colspan="4" id="formulabar" style="display: none"></div>
+    </div>
 
     <input id="insertgraphic" aria-labelledby="menu-insertgraphic" type="file" accept="image/*" style="position: fixed; top: -100em">
     <input id="selectbackground" aria-labelledby="menu-selectbackground" type="file" accept="image/*" style="position: fixed; top: -100em">