Updated FAQ to include section on CUDA library initialization failures

[Micky774]

CUDA library load/initialization errors have been fairly commonly reported in the past, and although error messages have improved on the XLA side, it is worth documenting an explanation and recommended solutions directly.

This PR adds an FAQ section dedicated to addressing these issues.

[Micky774]

cc: @pearu @hawkinsp

[jakevdp]

Thanks! Assigning @hawkinsp to review this info.

[Micky774]

@hawkinsp does this documentation change look sufficient for inclusion?

[Micky774]

@hawkinsp feedback has been addressed, lmk how it looks :)