Remove all traces of workspaces from the system.

[karenetheridge]

remove workspace tables and all queries to them:

• user_workspace_role
• workspace
• workspace_rack

removed endpoints:

• GET /workspace
• GET /workspace/:workspace_id_or_name
• GET /workspace/:workspace_id_or_name/child
• POST /workspace/:workspace_id_or_name/child?send_mail=<1|0>
• GET /workspace/:workspace_id_or_name/device?
• GET /workspace/:workspace_id_or_name/device/pxe
• GET /workspace/:workspace_id_or_name/device-totals
• GET /workspace/:workspace_id_or_name/rack
• POST /workspace/:workspace_id_or_name/rack
• DELETE /workspace/:workspace_id_or_name/rack/:rack_id
• GET /workspace/:workspace_id_or_name/relay
• GET /workspace/:workspace_id_or_name/relay/:relay_id/device
• GET /workspace/:workspace_id_or_name/user
• POST /workspace/:workspace_id_or_name/user?send_mail=<1|0>
• DELETE /workspace/:workspace_id_or_name/user/:target_user_id_or_email?send_mail=<1|0>

also affects output in endpoints:

• GET /user/me
• GET /user/:target_user_id_or_email

removed scripts and commands:

• bin/conch check_workspace_racks
• bin/conch clean_roles
• bin/conch workspace_to_build
• bin/conch workspaces
• bin/conch-db create-global-workspace