- Handling of rebuild IO from other replica according to metadata
- Removing code based on txg number

Signed-off-by: mayank <mayank.patel@cloudbyte.com>

  Snapshot created with provided metadata will be removed if (offset + length) == (end of metadata)
- Replaced dsl_pool_hold with dmu_object_own to hold snapshot in uzfs_get_io_diff
  Since, it was causing deadlock
- Functionality test for partial read from uzfs_get_io_diff

Signed-off-by: mayank <mayank.patel@cloudbyte.com>

- code changes according to review comments

Signed-off-by: mayank <mayank.patel@cloudbyte.com>

- changes according to review comments
- uzfs_open_dataset_init changed to uzfs_own_dataset for better
  readability
Signed-off-by: mayank <mayank.patel@cloudbyte.com>

- setting metavolblocksize to 512 bytes when creating volume through CLI

Signed-off-by: mayank <mayank.patel@cloudbyte.com>