Add cast_rules_to_readonly to share instances

- Add Database migration to introduce the column on the
  share instances model.
- Set the field to True if creating read-only secondary
  replicas, unset while promoting them.
- Set the field to True if drivers don't support writable access
  to migrating shares, or if using host assisted migration.
  Unset if migration fails, or is canceled.
- Expose the field via share-instances and share-replicas
  APIs to administrators.

Supporting read only-access rules is part of the minimum
driver requirements in manila.

APIImpact
DocImpact

Implements: bp fix-and-improve-access-rules

Co-Authored-By: Rodrigo Barbieri <rodrigo.barbieri@fit-tecnologia.org.br>

Change-Id: Ie8425f36f02cbcede0aaa9f3fe1f5f3cf23df8b8
2 files changed
tree: e6ae0add641d7c307e33ed0dced1d6e83363e91e
  1. manila_tempest_tests/