Improve lane pairing documentation

* Added an extended version of the image OSI_LaneBoundaries_And_CenterLine.svg
  that includes, connected by a junction.
  - The new image is called
    OSI_LaneBoundaries_And_CenterLine_Intersection.svg and will replace
    the old one in the Lane/Classification/Centerline section.
  - The old image will still be used in the LaneBoundary/BoundaryPoint
    section.

* Added a more precise description to Lane/Classification/lane_pairing
  on how antecessor and successor have to be set.

Signed-off-by: Fabian Pfeuffer <fabian.pfeuffer@capgemini.com>

Author: Fabian Pfeuffer