[GEOS-12149] GeoServer WMTS capabilities put query parameters in the wrong place in generated URLs

[fernandor777]

https://osgeo-org.atlassian.net/browse/GEOS-12149

This PR fixes WMTS capabilities URL generation so propagated query parameters, such as projecttoken, are appended after the existing WMTS query string instead of being injected into the middle of the URL path.

What changed:

• Refactored WMTS capabilities URL handling to keep base URLs and propagated query parameters separate until final serialization.
• Updated WMTS URL construction so resource and metadata backlinks preserve path placeholders and append propagated query parameters last.
• Added/updated WMTS tests to cover:
  • existing query parameters
  • no existing query parameters
  • correct placement of propagated parameters
  • regression coverage for capabilities and TileJSON outputs

Behavior after the change, generated URLs now follow the expected structure:

• .../rest/BasicPolygons/{style}/{TileMatrixSet}/{TileMatrix}/{TileRow}/{TileCol}?format=image/png&projecttoken=abc123
• .../rest/WMTSCapabilities.xml?projecttoken=abc123

Instead of malformed forms where query parameters appears before unresolved path segments.