[Dashboard] Enhance blob support

[fietser28]

Is your feature request related to a problem? Please describe. No just a feature request.

Describe the solution you'd like Add a few functions to better support handling and processing of blob contents:

• [ ] .toString() converts a blob to a string
• [ ] .size() returns the size of the blob content in bytes. This is important for pre allocating structures when extracting data from blob
• [ ] .slice(/blob/, /start/, /[end]/). This is important to avoid converting unnecessary amounts of data.

Describe alternatives you've considered Alternative for .toString() is: I don't have alternatives for the other methods (probably can be done in JS Eval)

Feel free to complement/change.