refactor: small fixes and refactors, update coreui styles

src/containers/TheHeader.vue

@@ -2,7 +2,7 @@
   <CHeader fixed with-subheader light>
     <CSidebarToggler 
       class="c-header-toggler ml-3"
-      v-c-emit-root-event:c-sidebar-toggle
+      v-c-emit-root-event:toggle-sidebar
     />
     <img
       class="c-header-brand mx-auto d-lg-none" 
@@ -11,12 +11,12 @@
       height="46" 
       alt="CoreUI Logo"
     />
-    <ul class="c-header-nav d-md-down-none mr-auto">
+    <CHeaderNav class="d-md-down-none mr-auto">
       <CHeaderNavItem class="px-3" to="/dashboard">Dashboard</CHeaderNavItem>
       <CHeaderNavItem class="px-3" to="/users" exact>Users</CHeaderNavItem>
       <CHeaderNavItem class="px-3">Settings</CHeaderNavItem>
-    </ul>
-    <ul class="c-header-nav mr-4">
+    </CHeaderNav>
+    <CHeaderNav class="mr-4">
       <CHeaderNavItem class="d-md-down-none mx-2">
         <i class="cui-bell"></i>
       </CHeaderNavItem>
@@ -27,7 +27,7 @@
         <i class="cui-envelope-open"></i>
       </CHeaderNavItem>
       <TheHeaderDropdownAccnt/>
-    </ul>
+    </CHeaderNav>
     <div class="c-subheader px-3">
       <CBreadcrumbRouter class="border-0"/>
     </div>