LU-10810 clio: SEEK_HOLE/SEEK_DATA on client side

LU-10810 clio: SEEK_HOLE/SEEK_DATA on client side

Patch introduces basic support for lseek SEEK_HOLE/SEEK_DATA
parameters in lustre client.

- introduce new IO type CIT_LSEEK in CLIO stack
- LOV splits request to all stripes involved and merges
  results back.
- OSC sends OST LSEEK RPC asynchronously
- if target doesn't support LSEEK RPC then OSC assumes
  whole related object is data with virtual hole at the end
- lseek restores released files assuming it is done prior
  the file copying.
- tool is added to request needed lseek on file
- basic tests are added in sanity, sanityn and sanity-hsm

Signed-off-by: Mikhail Pershin <mpershin@whamcloud.com>
Change-Id: I0728329d4bce71c441de581a439cde1aa873fd46
Reviewed-on: https://review.whamcloud.com/39708
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: Oleg Drokin <green@whamcloud.com>