metadump: Introduce metadump v1 operations

metadump: Introduce metadump v1 operations

This commit moves functionality associated with writing metadump to disk into
a new function. It also renames metadump initialization, write and release
functions to reflect the fact that they work with v1 metadump files.

The metadump initialization, write and release functions are now invoked via
metadump_ops->init(), metadump_ops->write() and metadump_ops->release()
respectively.

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>