[SVCS-479] Raise exception for copy/move replace folder that orphans itself.

[NyanHelsing]

Ticket

https://openscience.atlassian.net/browse/SVCS-479

Replaces: https://github.com/CenterForOpenScience/waterbutler/pull/274

Purpose:

Replace folder from inside folder deletes both

Changes:

• Updated waterbutler/core/provider.py
  • Add def replace_will_orphan
  • Update def move calls replace_will_orphan
  • Update def copy calls replace_will_orphan
• Update waterbutler/core/exceptions.py
  • Add class OrphanSelfError
• Update tests/providers/osfstorage/test_provider.py
  • Add test test_intra_copy_folder_orphan

Side effects

Folder move/copies that use conflict=replace may now be more costly

[NyanHelsing]

See previous PR for discussion https://github.com/CenterForOpenScience/waterbutler/pull/274

[coveralls]

Coverage decreased (-0.003%) to 91.981% when pulling e012a516771d097259946c596317ffc9b77eeff1 on birdbrained:ft/move-orphan-delete into 5c637a2affa8dfb43159ff80cf430c9ac5d369f8 on CenterForOpenScience:develop.

[NyanHelsing]

@cslzchen Can you note here what specifically blocks this PR that is resolved by #341?