Use `denormalized.trees` table to implement the routers under `/species`

We are using `public.trees` to query data for `/species` but it is slow, we now created a new table to denormalize the data to get higher performance, so please use the new table to implement this API again.

Some notes:
* Prerequisite: https://github.com/Greenstand/treetracker-denormalization/issues/1
* Please checkout the denormalized branch to work on and to create pull request.
* More details about denormalization is [here](https://docs.greenstand.org/web-map/denormalized-map-data)

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