Google search suggestions

[flightmansam]

Added search url (for english only).
Tentatively disabled search engine check in instantAnswerPlugin

[flightmansam]

TODO:
Decide whether instantAnswerPlugin needs to fetch a preferences option to always provide instant answers using DDG even if the default search engine isn't DDG.

[flightmansam]

@PalmerAL Is this okay to merge?

[PalmerAL]

I don't want to use the Google URL unless they have an official API we can use that they won't try to block. We could make this an option when you set a custom search engine though.

[gribanoveu]

Is any telemetry being sent to google at this point?

[flightmansam]

Not any more than manually putting in the URL in any browser.

[PalmerAL]

Oh, I'm realizing I never followed up on the DDG part of this PR, sorry. I believe the original reason for that restriction was due to a restriction in DDGs API terms, although I can't find anything supporting that anymore. They've since deprecated the API entirely and deleted all the documentation, so we really should figure out an alternative to use; I'm not sure at the moment what that would be though.