added an admin page stub

for users with the new attribute "isCompanyAdmin" set to true on their user_profile, the app will display a nav item for "Admin Panel". those users can navigate to the panel, and will be able to update/add/delete/etc companies, locations, etc...

In the view manager I've built in a security check so if a user without that flag tries to access it, they get the 403 permission denied error.