Add Startpage to the regional lists of search engines

[mgdx]

Startpage is defined upstream in prepopulated_engines.json but is only listed for two countries, DE and LI, so it is not offered anywhere else. Add it right after DuckDuckGo on every regional list, the same way the DuckDuckGo patch does, and capitalize its display name.

Startpage is a privacy respecting search engine: it does not profile its users, keeps no search history tied to them, and forwards queries to Google's index without exposing who is asking. That design also makes it one of the few privacy oriented engines whose result quality matches what users expect from a default engine, since it does not have to fall back on a smaller index of its own. Offering it next to DuckDuckGo gives users a second serious option that does not trade relevance for privacy.

Increment kCurrentDataVersion so that existing profiles pick up the new list instead of keeping the one they were created with.

[mateowoetam]

I would love to see startpage added to Vanadium as an option, would make it way less tedious to add it as the default search engine.