The sampling frequency should be read from the data

[celprov]

Stuff that needs to be addressed after the code developed for OHBM23.

For now, the sampling frequency as randomly chosen value. Please implement so that the sampling frequency gets read automatically from the data.

[goodalse2019]

Notes for my own help: BIDS accepted physio format will have the sampling frequency in the JSON file so if we are having it read in "BIDS" format then that could be how it is pulled.

[m-miedema]

We've talked about @maestroque implementing this in physutils! Hopefully physioQC will be able to make use of that package?

The idea is to be able to instantiate a Physio object from a BIDS folder with the appropriate labels and json info (e.g. subject label, sampling rate, etc).