Add a setting to disable the explorer tab or introspection

[benpigchu]

I don't want to send the IntrospectionQuery request to the server, but I still wnat to debug the cache. Because of that, I need a setting on this.
I can use a custom link to drop that request, but a setting on the devtools extension itself would be more helpful.

[arsinclair]

Can we have some traction here? On our end the introspection is disabled on the server, so the query is rejected, however quite unfortunately Apollo bundles a bunch of other queries together with introspection query, effectively causing all of them to drop.