feat: Add StudioHeader with optional AppMenu (#199)

* feat: Add StudioHeader with optional AppMenu

StudioHeader is a graft of Header with an additional optional AppMenu.
Some Frontend Apps use Menus in their custom headers to provide more
functionality in their apps. By adding this functionality in
StudioHeader, it will be easier for frontend apps in Studio to adopt
this component without it affecting the main Header component.

* test: Add tests for StudioHeader and AppMenu

* fix: Remove orderHistory

* fix: Remove Responsive components

* fix: Redefine User Menu for Studio

The userMenu in StudioHeader will be used more for Studio related items
such as Studio Home and Studio Maintenance. This requires new messages
and reestablishing the url destinations of these menu items.

* fix: Remove loggedOutItems

* fix: Remove AUTHN_MINIMAL_HEADER items

* fix: Remove unnecessary tests

Anonymous sessions do not exist in the Studio. And Studio is not Mobile
Ready. Tests of these kind are superfluous and have been removed.

* feat: Turn mainMenu into an optional prop

* test: Add test for optional mainMenu prop

* feat: Update snapshots

* fix: Remove ResponsiveContext

* fix: Remove href and update appMenu prop

Dropping the href because having a link that also works as a dropdown
can be mildly confusing. Changing menu (type, href, content ) triplet
to stick to the pattern; so we removed "menu". Also adding brackets around
the triplet. Lastly, updating test and snapshot.

Co-authored-by: Carlos Muniz <cmuniz@trcil.org>

.env.development

@@ -5,6 +5,7 @@ CSRF_TOKEN_API_PATH=/csrf/api/v1/token
 ECOMMERCE_BASE_URL=http://localhost:18130
 LANGUAGE_PREFERENCE_COOKIE_NAME=openedx-language-preference
 LMS_BASE_URL=http://localhost:18000
+STUDIO_BASE_URL=http://localhost:18010
 LOGIN_URL=http://localhost:18000/login
 LOGOUT_URL=http://localhost:18000/logout
 MARKETING_SITE_BASE_URL=http://localhost:18000