Create or update the breadcrumbs in the site administration
pages where it is required.
Highlight the corresponding site adminstration tab.
Highlight the primary nav to Site administration when user
is navigating to any of the site administration pages.
Also changed the boostnavbar so that the nodes in the secondary
navigation are not shown in the breadcrumbs when user is in site
administration page.
Generally, we want to avoid displaying any breadcrumb nodes which are
already present in the primary navigation menu. Currently, this is done
by manually specifying which breadcrumb node (by its identification key)
should be removed. This change provides more reliable, automatic removal
of these breadcrum nodes by utilizing the exising method
remove_items_that_exist_in_navigation().
Introduces an additional type identifier argument to the remove() method.
This argument is optional and can be used to further specify the type of
the breadcrumb node we want to remove. This can add additional security
that the correct item is being removed.
Avoids removing the section breadcrumb nodes in the course module
context when the course uses the 'One section per page' layout.
Additionaly, it also removes the Courses and Category breadcrumb
nodes in the module contexts to be consistent with the way the
breadcrumbs are displayed in the course context.
Reimplements the navbar in the site administration pages and removes
any navbar nodes that are already present in the primary or secondary
navigation menu.
Luca Bösch