Reorg directories and add CORE-V-eXtension-Interface

[MikeOpenHWGroup]

@DBees, this looks like a big change (60 files affected), but it is rather simple:

• Create directory CV32E40P-ProjectScheduleUpdates and move all CV32E40P project status presentations there.
• Create directory VerificationTaskGroupPresentations and move all non-core-specific VTG presentations there.
• Create directory CVA6 for CVA6-specific presentations.
• Create directory CORE-V-eXtension-Interface for a couple of new verification presentations on this topic.

Signed-off-by: MikeOpenHWGroup mike@openhwgroup.org