Adding support for unit field in structured search.

[sweco-semhul]

If libpostal finds it in input use it for searching.
E.g. if address is set to: "Rådhusvej 20 1 th"
libpostal will parse it to:

[
    {
		"label": "road",
		"value": "Rådhusvej"
	},
	{
		"label": "house_number",
		"value": "20"
	},
	{
		"label": "unit",
		"value": "1 th"
	}
]

then, as for house_number, unit should be added to parsed_text and removed from parsed_text.address to result in:

"parsed_text": {
	"number": "20",
	"street": "Rådhusvej",
	"unit": "1 th"
} 

today the result is

"parsed_text": {
	"number": "20",
	"street": "Rådhusvej  1 th"
} 

this PR resolves it and adds a test for it.

[orangejulius]

Hello again @sweco-semhul,
This PR looks good, and doesn't break any acceptance tests. Thanks!

And although it's been a while, we still plan on merging your other PRs related to pelias/pelias#618. It's on the todo list...somewhere with everything else to do in this wild year :)

[pelias-bot]

🎉 This PR is included in version 3.33.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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