Revert "packages: Add qcow-tool as xapi's dependency"

This reverts commit 240b774.

Instead of using a ready-made CLI binary from qcow-tool (which does not
seem to be easily possible with dune), we will use a minimal binary
defined locally in xapi.

Signed-off-by: Andrii Sultanov <andriy.sultanov@vates.tech>

Author: last-genius

packages/mirage-block-combinators/mirage-block-combinators.3.0.2/opam

@@ -50,7 +50,7 @@ depends: [
   "ppx_deriving"
   "psq"
   "ptime"
-  "qcow-tool"
+  "qcow-stream"
   "qcheck-alcotest"
   "qcheck-core"
   "re"