New page to login (page/login/) as admin. Cleaning and new button added in admin page to restart the current session. Flash messages added.
Merge branch 'develop' into feature/1277-admin-section

Conflicts:
	poieticgen/api.rb
	views/layout.haml
	views/page_admin.haml
	views/stylesheets/_common.scss
stylesheets: disable CSS for page admin.
Merge branch 'feature/1277-admin-section' into develop