💂‍Think about the data structure for tests

[philipp-baumann]

An integral validity check is to extract the exact block infos of the example files via Bruker OPUS software and then store these more or less plain text in our own file in tests.
This implies we need a proper data structure such as JSON with either plaintext or base64 encoded fields.

[philipp-baumann]

we introduced basic tests in version 0.6.0