qcodes instruments are not thread safe

Some of the instrument drivers are not thread safe. This means that a `Loop` could case problems with the `use_threads` option set to `True`.

We should at least document the thread safety of instruments (parameters) and consider setting `use_threads` to `False`

Start by reviewing the instrument drivers and the Loop use_threads option described in the issue. Determine which instrument parameters are thread safe, document that behavior, and clarify whether use_threads should default to False; the issue is done when the supported behavior and decision are recorded.

Written by the indexing model from the issue text.