feat(query-splitting) first try at returning "query" in geocode split in placeholder

[blackmad]

This change is in preparation for experimenting with placeholder doing more of the admin splitting work that parser & libpostal currently do. It adds a "query" to the placeholder responses which is the left most tokens in the query that are not matched by placeholder.

It adds a /tokenize2 endpoint (which I think is for debugging only?) to expose this
it adds "query" to the results from /search

internally, it primarily adds a remainder: {before: string, after: string} to the "group" object in the code.

It is a tiny bit based off of this stale PR: #37

demo frontend updated

[blackmad]

this change seems broken. will keep looking.

[{phrase: "saunders st rego park", query: "6307", id: 420782897, name: "Rego Park",…}]
0: {phrase: "saunders st rego park", query: "6307", id: 420782897, name: "Rego Park",…}
geom: {area: 0.000259, bbox: "-73.871429,40.711338,-73.85173,40.73627346", lat: 40.727122, lon: -73.862152}
id: 420782897
languageDefaulted: false
lineage: [{borough: {id: 421205767, name: "Queens", languageDefaulted: false},…}]
name: "Rego Park"
phrase: "saunders st rego park"
placetype: "neighbourhood"
query: "6307"

[blackmad]

this seems happier now

[blackmad]

Actually, looking back at this work, it's still an interesting base to play with. tokenize2 could probably be called tokenizeStructured or something else smarter. @missinglink equally happy to abandon this or keep working on it, what do you think?