Accept substitutions in build configuration names

[ilg-ul]

Implement something similar to GitHub Actions strategy matrix.

    "strategy": {
      "matrix": {
        "builder": ["cmake", "meson"],
        "toolchain": ["gcc", "clang"],
        "buildType": ["debug", "release"]
      }
    },
    "buildConfigurations: {
      "test-native-{{ matrix.builder }}-{{ matrix.toolchain }}-{{ matrix.buildType }}": [
        "xpm run prepare --config native-{{ matrix.builder }}-{{ matrix.toolchain }}-{{ matrix.buildType }}",
        "xpm run build --config native-{{ matrix.builder }}-{{ matrix.toolchain }}-{{ matrix.buildType }}",
        "xpm run test --config native-{{ matrix.builder }}-{{ matrix.toolchain }}-{{ matrix.buildType }}"
      ]
    }