WMTS visualization

WMTS visualization endpoint for a given catalog item. This endpoint **should not be forged** but retrieved from the `_links` map in each catalog response. WMTS protocol shall be used to request this endpoint. Please refer to the WMTS documentation. Currently supported versions are `1.0.0`. The visualization is different according to processing level and product type: - SENSOR / bundle: on the fly orthorectification with panchromatic and multispectral images - ORTHO / bundle: panchromati...