refactor(app): create a composed header component [EE-2329] (#6326)

* refactor(app): create a composed header component

refactor(app): support single child breadcrumbs

fix(app): fix breadcrumbs warning

* refactor(app): import breadcrumbs

* refactor(app): support object breadcrumbs

* chore(app): write tests for header components

.eslintrc.yml

@@ -94,3 +94,5 @@ overrides:
       - 'plugin:jest/style'
     env:
       'jest/globals': true
+    rules:
+      'react/jsx-no-constructed-context-values': off