Add SDK version parsing logic for txt files to QtCreator MCU Support plugin

Currently for the Infineon Traveo II platforms kits, the SDK version is parsed from the SDK installation path.

"boardSdk": {
        "envVar": "TVII_GRAPHICS_DRIVER_DIR",
        "setting": "TVII_GRAPHICS_DRIVER_DIR",
        "versions": [
            "V2.3.0"
        ],
        "id": "TVII_GRAPHICS_DRIVER_DIR",
        "label": "Graphics Driver for TRAVEO™ T2G Cluster Series",
        "cmakeVar": "QUL_BOARD_SDK_DIR",
        "type": "path",
        "defaultValue": "C:/TVII-GraphicsDriver",
        "optional": false,
        "versionDetection": {
            "regex": "V\\d+\\.\\d+\\.\\d+"
        }
    }

This likely won't work for a customer as the default SDK installation path is C:/TVII-GraphicsDriver without any info about the version.

We should parse instead the text file README_SDK.txt which contains the SDK version information.

In order to do so another parsing logic should be added in src/plugins/mcusupport/mcusupportversiondetection.cpp, to search for regular expressions in plain text files similarly to what we do for XML files. The kit files should be updated to use the new parsing mechansim.