Remove support of manual mode for loading tapes
In CASTOR there was a manual mode for loading and unloading tapes. It was ported to CTA, but eventually it became impossible to use it. Since no other institutions explicitly asked for this mode and we cannot guarantee that it will work in the future, we shouldn't keep the code.
At the dev meeting (04/02/2022) we decided the support for this mode should be dropped.
All occurrences of TAPE_LIBRARY_TYPE_MANUAL
in tapeserver and mediachanger must be removed.