sap_install_media_detect: Make the role idempotent

[berndfinger]

The role will copy or move files to certain directories and also extract files.
So we either need to decide what the starting point is or we need to be able to describe the desired outcome.
Describing the desired outcome is nearly impossible because the contents of files might change.
If we can get back to the starting point (all files in the same main directory, either local or remote), then we have reached idempotency.

[berndfinger]

Solved by commit berndfinger@b625184 .