OpenOCDDriver: disable default server ports

[ozan956]

Description

OpenOCD starts GDB, telnet, and TCL servers on fixed default ports. When
multiple boards on the same exporter bootstrap concurrently, the second
OpenOCD instance fails to bind these ports.

Disable the server ports before loading OpenOCD configuration files.
OpenOCDDriver does not provide a lifecycle for using or stopping these
servers, while disabling them allows parallel bootstrap operations.

Configurations that intentionally require a server interface can re-enable
the required port before init.

Checklist

• Documentation for the feature
• Tests for the feature
• The arguments and description in doc/configuration.rst have been updated
• Add a section on how to use the feature to doc/usage.rst
• Add a section on how to use the feature to doc/development.rst
• PR has been tested
• Man pages have been regenerated

Tested with:

pytest -q tests/test_openocd.py
ruff check labgrid/driver/openocddriver.py
ruff format --check labgrid/driver/openocddriver.py

[Emantor]

That change makes sense to me, a different option would be to rewrite the exporter to control the openOCD invocation similar to how we handle serial ports with ser2net.