Default to the latest Holoscan SDK version (4.4.0).

This updates:

- the 23 application, module, operator, and tutorial metadata files
included in the reviewed HSDK 4.4 validation set;
- HoloHub, application, and module defaults and templates;
- the networking package and debugging tutorial container references;
and
- the consolidated Holoscan CLI documentation and tests.

The DAQIRI socket ping metadata is intentionally unchanged because it
was not included in the HSDK 4.4 validation set. Its earlier rename from
basic networking is not treated as validation evidence.

The prior `v4.3.0-dgpu` devcontainer reference is unavailable. The first
commit corrects it to the published `v4.3.0-cuda12-dgpu` tag. The second
commit advances that explicit lane to `v4.4.0-cuda12-dgpu` with the rest
of the release bump. The 4.4 public container was verified before
opening this PR. This change follows the prior HSDK 4.3 bump in #1590
while accounting for paths that have since moved or been consolidated.

Validation:

- `./holohub lint --install-dependencies`
- `./holohub lint`
- `pytest -q utilities/cli/tests/test_holoscan_cli_consolidation.py`
against published `holoscan-cli==4.4.0` (6 passed)
- HoloHub `run-container` dry-run for lint dependency installation and
lint execution

The full container lint remains covered by PR CI because Docker is
unavailable on the preparation host.

---------

Signed-off-by: Jean-Christophe Fillion-Robin <jcfr@nvidia.com>