Add support for environment-based config in hscdata module

This commit adds a new feature to the hscdata module, allowing users to specify the configuration through an environment variable named 'HSCDATA2_CONFIG_B64_JSON'. If this environment variable is set, the module will load the configuration from its value as a JSON string. If the environment variable is not set, the module will fall back to loading the configuration from the 'config.json' file as before.

This change provides greater flexibility for users who prefer to manage their configurations using environment variables.