Introduce IdeUrlTrackingParametersProvider service which is overriden in products to append necessary parameters, remove 'fromIDE' parameter from *ApplicationInfo.xml files.
(IDEA-CR-27675, IDEA-183268)

Link to xsd schema is added, unused attribute 'textX' is removed, tags are rearranged to meet the schema constraints, position of JetBrains logo on 'About' popup is corrected (IDEA-149734).

edu --> educational-python
educational --> educational-core
interactive-learning --> student

(cherry picked from commit 03f32042b546df08116ff1ca5c6262cec3672803)
(cherry picked from commit 152318d3)

(cherry picked from commit c1dfdffae65c9d5f28b913fac2f7027a068634ce)
(cherry picked from commit 70968861)

cleanup: removed __PACKAGE_CODE__ placeholder from *ApplicationInfo.xml files where it's not needed (it's used in IDEA Ultimate and RubyMine only), added javadoc to 'getPackageCode' method;
previously this placeholder was included as is in all IDE distributions which may give an impression that it wasn't replaced by mistake and that it should be replaced by product code that will lead to problems (IDEA-147946)