Migrate to menuinst v2

[gdementen]

When testing pixi, I realized our menu definitions (larray-editor\condarecipe\larray-editor\larray-editor.json) are still using v1 syntax while a v2 has existed for a while. This is required for pixi support.

Here is what I used for v2 so far:

{
    "$schema": "https://json-schema.org/draft-07/schema",
    "$id": "https://schemas.conda.io/menuinst-1-1-3.schema.json",
    "menu_name": "LArray",
    "menu_items": [
        {
            "name": {
                "target_environment_is_base": "LArray Editor",
                "target_environment_is_not_base": "LArray Editor ({{ ENV_NAME }})"
            },
            "description": "LArray Editor",
            "activate": false,
            "terminal": false,
            "command": ["{{ SCRIPTS_DIR }}\\larray-editor.exe", "%*"],
            "icon": "{{ MENU_DIR }}\\larray.ico",
            "platforms": {
                "win": {
                    "file_extensions": [
                        ".h5"
                    ]
                }
            }
        },
        {
            "name": "LArray Documentation",
            "description": "LArray Documentation",
            "command": ["{{ BASE_PYTHONW }}", "-m", "webbrowser", "http://larray.readthedocs.io/en/0.35"],
            "icon": "{{ MENU_DIR }}/larray-help.ico",
            "platforms": {
              "win": {}
            }
        },
    ]
}