Add device reset

[thorstendb-ARM]

Adds:

Custom Reset (configured via launch.json).
Issue: eclipse-cdt-cloud/cdt-gdb-adapter#359

Testing:

Required: eclipse-cdt-cloud/cdt-gdb-adapter#365
In a target project, launch.json, add this. The command uses pyOCD but can be any other.

    "configurations": [
        {
            "name": "pyOCD cdt-gdb-adapter",
            ...
            "customResetCommands": [
                "monitor reset halt hardware",
            ],
        },

Note:

The GUI update depends on an asynchronous event from GDB (such as Target STOPPED), likely triggered by the connected target debugger. If this event is absent (e.g. in current pyOCD), test it by performing a single step-into after pressing the Custom Reset button.

[jreineckearm]

We do have some lightweight documentation in the README.md. Could you please add the new setting there, too?

[jreineckearm]

Changes LGTM and work nicely with eclipse-cdt-cloud/cdt-gdb-adapter#365 . The other PR against the adapter needs to be merged and released first though.

Approved but merging only tomorrow (CET) to give others time to review, too. (CC: @jonahgraham , @asimgunes).

[jonahgraham]

Other than the changelog comment I approve of this.

[jreineckearm]

Changelog looks good now, thanks for spotting this, @jonahgraham ! I agree that we should restrict issue links in the changelog to Eclipse CDT Cloud repo issues.

[jreineckearm]

Waiting with merge until complementary adapter change is merged and released.