Rename `PutContext` to `ContextWithToken` and implement its constructor as a
separate function in order to reuse it in other RPCs.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
If container is created via session, then session token should be written to
it.
Write session token from request meta header to `Container` structure which
is passed to `wrapper.Put` function.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
