Add setting for disabling caching of IDE contextual queries

[hvitved]

Like we have

"codeQL.astViewer.disableCache": true

today, it would be nice to have similar settings for other contextual queries, e.g. jump-to-definition.

[aeisenberg]

I am proposing using "codeQL.contextualQueries.disableCache": true. This setting will apply to both jump to def and find refs.

@hvitved do you use the CFG viewer? Do you want there to be a way to avoid the cache here as well? I propose using the same AST viewer setting.

[hvitved]

Would certainly make sense to have a similar option for the CFG viewer. Last I tried using the CFG viewer, I ran into a bug, but can't remember which. I'll give it another try.