Update SampleDB example

[FlorianRhiem]

The .eln file now contains strings for contentSize and uses . as separator for nested flexible metadata rather than /.

[NicolasCARPi]

In my case, eLab chokes on the mentions because it's not an array. But that an issue on eLab side, as it's perefectly valid to use an object here. I just need to implement a robust parser instead of assuming types or incorrectly figuring it out...