Search prompt implementation

[turkhale]

UI, UX, and overall implementation of the search prompt, including the syntax and rules of selection of composed domain topics and terms.

[turkhale]

I would've liked to select domain terms and topics visually in the prompt, similarly to how Bing structures and highlights the text in the immersive reader mode with nouns, adjectives, verbs, etc. Maybe even show at the backplane search results from those terms pages as a context for search results.