Bug 36206: Expose administration page to users with plugins_admin permission

Bug 36206: Expose administration page to users with plugins_admin permission

This patch updates the intranet home page logic such that the
administration button appears for those users with just the 'admin'
subpermission of plugins to allow them to access such plugins.

We also update the display logic found inside the admin-home page so
that user see plugin management appropriately.

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>