Fix redirection to a custom page after login

By default, user is redircted to the initial document default view after login:

<page view-id="/nxstartup.xhtml"
action="#

{startupHelper.initDomainAndFindStartupPage('Default domain', 'view')}

" />

Comments also advise how to customize the redirection view:

<!-- To redirect to the user dashboard instead, use instead:

<page view-id="/nxstartup.xhtml"
action="#

{startupHelper.initDomainAndFindStartupPage('Default domain', 'user_dashboard')}

" />
-->

This won't work by default as method initDomainAndFindStartupPage waits for a document view id, not a jsf outcome id => if 'user_dashboard' does not match a view defined on the document ecm type, the document default view will be used, and 'user_dashboard' will be ignored.