random: added a random driver interface

how should this be designed?

I see this PR as a discussion forum for this long standing discussion
I would like to add some more information/warnings about the source of randomness and the quality of randomness here, how about:
```
NOTE: The quality of the random data read from this interface is highly dependent on hardware dependent implementation. Most platforms utilize a hardware (Pseudo) Random Number Generator. The quality of the generated random data can be however very different.

PLEASE REFER TO YOUR PLATFORMS IMPLEMENTATION ABOUT INFORMATION ABOUT THE QUALITY OF RANDOMNES!
```
Or something similir?