Add hakunapi-tiles-core, the OGC API - Tiles model and tiles configuration

[jampukka]

New community module (src-community/hakunapi-tiles-core, depends only on hakunapi-core). It is the model and configuration for OGC API - Tiles; nothing serves tiles yet. The servlet, the tile sources and the generator come in later PRs, so several classes here have no caller until then.

Key classes:

• Tileset model (concept, not a class)
  • A tile layer is an id plus the tile matrix sets it is published in; a source turns an address (matrix set, matrix, row, col) into a Tile
  • Vector and map (raster) layers are separate, mirroring /collections/{id}/tiles and /map/tiles
• VectorTileSource / MapTileSource
  • ServiceLoader extension points, the data-plane counterpart of SimpleSource; a source parses its own tiles.layers.<id>.* keys into a layer and later serves its tiles
• Tile / BytesTile / BodyTile
  • A tile is an address, a media type and something that can write itself; BytesTile holds finished bytes, BodyTile a lazy TileBody so a generating source encodes straight into the response
• TileMatrixSet / TileMatrix / DefaultTileMatrixSetRegistry
  • OGC 17-083r4 tiling schemes; the registry is seeded with WebMercatorQuad and the sets named in configuration
• TilesConfigParser
  • Wraps HakunaConfigParser so core stays free of the tiles model; derives matrix sizes from extent and resolution and rejects sets that are not a whole number of tiles per level
• TileLocator / AcceleratedTileLayer / AcceleratedTilesets
  • For stores where a tile is one contiguous run in a file: location kept in memory as a packed offset and length, so a front end can send the byte range itself
  • Accelerated means we can utilize sendfile()
• ZoomRoutedVectorTileSource / ZoomBacking
  • zoom-routed-vector: one layer backed by several sources by zoom range, optionally extracting one MVT layer from a backing's tile (MvtLayerExtract); a zoom no backing covers answers with an empty tile rather than 404
• schemas
  • TileJSON and OGC tileset documents, plain getter classes as elsewhere in the repo

Behaviour changes:

• ConformanceClass gains the OGC API - Tiles and tile matrix set URIs. Nothing claims them yet, so /conformance is unchanged
• HakunaConfigParser gains getProperties(), so ZoomRoutedVectorTileSource can derive a parser for its backings. The returned object is the shared one and must not be mutated