Option to override the LTI skipacceptlaunchpage settings

In some cases it is handy that the launch page can be skipped in the LTI course element, specially when the admins of the course know which LTI elements are embedded and the transmission of data is not a problem. 

In case of institutions with many authors (e.g. University), the admins have no idea which LTI resource is embedded by the various course authors, thus skipping of the launch page should not be possible. On the launch page the user is informed about the data that is transferred to the LTI producer, in those cases the launch page is mandatory. 

A new option in olat.properties is added to systemwide override the setting from the course element. 

A new default setting is added:

course.node.basiclti.force.launchpage=false

If set to false, everything behaves as today. 

If set to true, the option in the course editor is removed and any variable stored in the course node is overridden. 

Things to consider: 

• Loading of cours nodes with the option must not remove the option from the config, it ist just not applied in the run
• Creating of new nodes should include the option, so that exporting and importing into another OO does not lead to a problem. 
• This new config must only be applied to the LTI course element. Other usage of the LTI infrastructure such as the edubook and card2brain course element must not show the start page.