Remove Oracle-InstantClient

[Geogouz]

Following rucio/rucio#7760, we should apply the changes here too. These involve the removal of Oracle's Instant Client and also the removal of its dependencies when no longer needed. The later can be handled more thoroughly in #420

[Geogouz]

Since we introduced support for both thick and thin mode, let's close this issue as we are going to keep the instant client which is used for the thick mode.