add timestamp to measurements and delay start (dragoon/komodo!111)

- add a timestamp to all the measurements of the _diversity_ from `inbreeding/mod.rs`
- allow to delay the measurement starts with `--measurement-schedule-start`, to help completing already existing measurements

>  **Important**  
> existing measurement files will have to change shape from
> ```
> table<strategy: string, diversity: list<float>>
> ```
> to
> ```
> table<strategy: string, diversity: table<t: int, diversity: float>>
> ```