AT:

• the import description in the documentation reflects the current state
• the import performance overview is updated to the Optimize 2.1.0 version
• the import overview and the import procedure sections are merged
• All links are working again

Context:
There are some outdated statements like "Optimize does not own the data of the engine. The Optimize dataset can always be removed and reimported or adapted to the needs of Optimize." I am also not sure if the illustrations on the Import Procedure page are still correct.