Updated triggers UI

Closes #14090

app/assets/stylesheets/framework/tw_bootstrap_variables.scss

@@ -153,7 +153,7 @@ $nav-link-padding: 13px $gl-padding;
 //== Code
 //
 //##
-$pre-bg:           #f8fafc !default;
+$pre-bg:           #f4f7fd !default;
 $pre-color:        $gl-gray !default;
 $pre-border-color: #e7e9ed;
 

app/views/projects/triggers/_trigger.html.haml

 %tr
   %td
-    .clearfix
     %span.monospace= trigger.token
 
   %td
@@ -9,6 +8,5 @@
     - else
       Never
 
-  %td
-    .pull-right
-      = link_to 'Revoke', namespace_project_trigger_path(@project.namespace, @project, trigger), data: { confirm: 'Are you sure?'}, method: :delete, class: "btn btn-danger btn-sm btn-grouped"
+  %td.text-right
+    = link_to 'Revoke', namespace_project_trigger_path(@project.namespace, @project, trigger), data: { confirm: 'Are you sure?'}, method: :delete, class: "btn btn-warning btn-sm"

app/views/projects/triggers/index.html.haml

 - page_title "Triggers"
-%h3.page-title
-  Triggers
 
-%p.light
+.row.prepend-top-default.append-bottom-default
+  .col-lg-3
+    %h4.prepend-top-0
+      = page_title
+    %p
       Triggers can be used to force a rebuild of a specific branch or tag with an API call.
-
-%hr.clearfix
-
--if @triggers.any?
-  .table-holder
+  .col-lg-9
+    %h5.prepend-top-0
+      Your triggers
+    - if @triggers.any?
+      .table-responsive
         %table.table
           %thead
             %th Token
             %th Last used
             %th
           = render partial: 'trigger', collection: @triggers, as: :trigger
-- else
-  %h4 No triggers
+    - else
+      %p.profile-settings-message.text-center.append-bottom-default
+        There are no triggers to use, add one by the button below.
 
-= form_for @trigger, url: url_for(controller: 'projects/triggers', action: 'create'), html: { class: 'form-horizontal' } do |f|
-  .clearfix
-    = f.submit "Add Trigger", class: 'btn btn-success pull-right'
+    = form_for @trigger, url: url_for(controller: 'projects/triggers', action: 'create') do |f|
+      = f.submit "Add Trigger", class: 'btn btn-success'
 
-%hr.clearfix
-
--if @triggers.any?
-  %h3
+    %h5.prepend-top-default
       Use CURL
 
     %p.light
@@ -38,7 +37,7 @@
              -F token=TOKEN \
              -F ref=REF_NAME \
              #{builds_trigger_url(@project.id)}
-  %h3
+    %h5.prepend-top-default
       Use .gitlab-ci.yml
 
     %p.light
@@ -53,7 +52,7 @@
           type: deploy
           script:
             - "curl -X POST -F token=TOKEN -F ref=REF_NAME #{builds_trigger_url(@project.id)}"
-  %h3
+    %h5.prepend-top-default
       Pass build variables
 
     %p.light
@@ -62,7 +61,7 @@
       to API request.
       The value of variable could then be used to distinguish triggered build from normal one.
 
-  %pre
+    %pre.append-bottom-0
       :plain
         curl -X POST \
              -F token=TOKEN \