FIX: uses tippy for popover (#15409)

Note this commit also introduce a new {{d-popover}} component, example usage:

```hbs
{{#d-popover |state|}}
  {{d-button label="foo.things" class="d-popover-trigger"}}

  <div class="d-popover-content">
    Some content
  <div>
{{/d-popover}}
```

lib/tasks/javascript.rake

@@ -148,8 +148,18 @@ def dependencies
     }, {
       source: '@popperjs/core/dist/umd/popper.js.map',
       public_root: true
-    },
-    {
+    }, {
+      source: 'tippy.js/dist/tippy.umd.js'
+    }, {
+      source: 'tippy.js/dist/tippy.umd.js.map',
+      public_root: true
+    }, {
+      source: 'tippy.js/dist/tippy.css',
+      destination: '../../../app/assets/stylesheets/vendor'
+    }, {
+      source: 'tippy.js/dist/svg-arrow.css',
+      destination: '../../../app/assets/stylesheets/vendor'
+    }, {
       source: 'route-recognizer/dist/route-recognizer.js'
     }, {
       source: 'route-recognizer/dist/route-recognizer.js.map',
@@ -206,6 +216,14 @@ def public_path_name(f)
   f[:destination] || node_package_name(f)
 end
 
+def absolute_sourcemap(dest)
+  File.open(dest) do |file|
+    contents = file.read
+    contents.gsub!(/sourceMappingURL=(.*)/, 'sourceMappingURL=/\1')
+    File.open(dest, "w+") { |d| d.write(contents) }
+  end
+end
+
 task 'javascript:update_constants' => :environment do
   task_name = 'update_constants'
 
@@ -330,14 +348,12 @@ task 'javascript:update' => 'clean_up' do
       FileUtils.cp_r(src, dest)
     end
 
-    # use absolute path for popper.js's sourcemap
     # avoids noisy console warnings in dev environment for non-homepage paths
     if dest.end_with? "popper.js"
-      File.open(dest) do |file|
-        contents = file.read
-        contents.gsub!("sourceMappingURL=popper", "sourceMappingURL=/popper")
-        File.open(dest, "w+") { |d| d.write(contents) }
-      end
+      absolute_sourcemap(dest)
+    end
+    if dest.end_with? "tippy.umd.js"
+      absolute_sourcemap(dest)
     end
   end