Lang: typo in maintenance plugin key

MAINTENANCE_PLUGIN_SLOT_DESC
Typo in lang key of Javascript fields description

^ Javascripts_Slot_Desc (had to be plural)
Lang: removed (unrendered) HTML markup from field labels.

- THEME_SLOT_DESC
- MAINTENANCE_PLUGIN_SLOT
Lang: order of help section entries in CONSTRUC2_DESCRIPTION

Full help text still missing, and might as well become an external (help) file all along...
Merge lab into dev110

^ Typo in lang key of Javascript fields description
^ Lang: removed (unrendered) HTML markup from field labels.
^ Lang: order of help section entries in CONSTRUC2_DESCRIPTION
HTML: cleanup content shared helpers
Add wrapper to content router in ContentLayoutHelper
Add missing support for 'access-view' param for items in blog views.

Despite items were ACL restricted, they appeared in blog views.
Changed blog item and links markup to override output with a "login to access" message.
Merge lab into dev110

* HTML: cleanup content shared helpers
* Add wrapper to content router in ContentLayoutHelper
* Add missing support for 'access-view' param for items in blog views.