Shim ui/autocomplete_providers into legacy data plugin

[lukeelmers]

This is something APM & Infra/Logs UI teams will be needing in order to migrate to NP. We had previously discussed locating this in data.query service, but exact location is yet to be determined, pending some design work that @lizozom is doing.

• Convert index.js -> index.ts
• Move contents of ui/autocomplete_providers into data plugin (service location TBD, should be discussed with @lizozom), and expose via shim
• Re-export from ui/autocomplete_providers for backwards compatibility

Related to #44377

[elasticmachine]

Pinging @elastic/kibana-app-arch

[lizozom]

IMO, there's no need to migrate the code at all, as this code is just a wrapper.
It can be also moved straight to NP.

These are the steps I would take:

1. Add the autocomplete_provider types to src/plugins/data/public/types.
2. Add a map named autocompleteProviders to data plugin, initialized in the constructor.
3. Add the autocomplete.addProvider method to the setup contract. The input argument language should default to query.
4. Add the autocomplete.getProvider method to both setup \ start contracts.
5. Update usages of these methods in code (addAutocompleteProvider is used just once, getAutocompleteProvider is used just a few), getting them from npSetup \ npStart imports.
6. Make sure to the update the data plugin mock and maybe add some basic tests?