Temporarily revert preferedFeatures addition

Squashed: revert "Jolla: Add platform and preferedFeatures for tutorial parser"
This reverts commit a5e6696d0c5a786a72300a8ea83fc28d5def36b3.
Squashed: revert "Jolla: Add preferredFeatures support for welcomepage"
This reverts commit e3649e2a7ccaac1982d7f35ed5a55e926ea84f0f.
Squashed: revert "Jolla: Add preferredFeauters to example template"
This reverts commit af0ca3f9147312790ed27efd00d7c010edd09df3.

Related functionality is to be rewritten after 3.1 is merged.
Temporarily revert "Read settings file for loading external tutorials"

This reverts commit 29a4c9bfdacd3c721f47abc764efc6db87533c66.

Related functionality is to be rewritten after 3.1 is merged.
Temporarily revert "Jolla: Mark Android and QNX plugins as experimental."

This reverts commit 79b9b78528d669b18620095bdc40a7195d295670.

Related functionality is to be rewritten after 3.1 is merged.
Temporarily revert "Jolla: Remove wizards which do not properly work with SailfishOS"

This reverts commit 6e20d1f9d6cbbf01570ae58c18b2610970443e62.

Related functionality is to be rewritten after 3.1 is merged.