Bundle the Natural Earth populated-places table with audit coverage

Adds the project-authored gazetteer table derived from the Natural
Earth 1:10m Populated Places dataset (public domain): 7342 rows, one
per populated place, with the NE id as the stable record id, the
transliterated ASCII name (NAMEASCII), alternate names, WGS84 point
coordinates, ISO 3166-1 alpha-2 country code, the admin-1 name as the
v1 containment element, POP_MAX, featureClass CITY, and the external
identifiers Natural Earth publishes (wikidata, geonames, whosonfirst)
as provenance-tagged attributes. The full derivation record (source,
mirror commit, extraction date, field mapping, public-domain
dedication) is in the file header.

The table is deliberately pure ASCII in v1: non-ASCII primary names
are carried as the ASCII transliteration Natural Earth provides, with
the Unicode forms omitted; the folded matching chain keeps accented
queries working against the ASCII rows. The audit test enforces the
header's claims row by row: row-count floor, pure-ASCII bytes, no
duplicate ids, country-code shape (the emoji-layer join key), lat/lon
range, the attribute-key whitelist, and deterministic lookups.

LICENSE gains the Natural Earth public-domain section; per the ASF
guidance for public-domain data there is no NOTICE entry.

Author: krickert

LICENSE

@@ -418,3 +418,21 @@ opennlp-core/opennlp-runtime/src/test/resources/opennlp/tools/tokenize/uax29
     not be used in advertising or otherwise to promote the sale, use or other
     dealings in these Data Files or Software without prior written
     authorization of the copyright holder.
+
+The following applies to the bundled gazetteer data in
+opennlp-extensions/opennlp-geo/src/main/resources/opennlp/geo
+(naturalearth-populated-places.txt). This table is a derivation of the
+Natural Earth "Populated Places" dataset (https://www.naturalearthdata.com/),
+which is dedicated to the public domain by its terms of use
+(https://www.naturalearthdata.com/about/terms-of-use/):
+
+    All versions of Natural Earth raster + vector map data found on this
+    website are in the public domain. You may use the maps in any manner,
+    including modifying the content and design, electronic dissemination,
+    and offset printing. The primary authors, Tom Patterson and Nathaniel
+    Vaughn Kelso, and all other contributors renounce all financial claim
+    to the maps and invites you to use them for personal, educational, and
+    commercial purposes.
+
+    No permission is needed to use Natural Earth. Crediting the authors is
+    unnecessary.