First implementation of GeoNetwork 2.10 integration for sir-admin viewer

* Early version of this integration for #85848 task.
* Added GeoNetwork js library
* Manage login in actual proxy
* Added a simple manager to envelop GeoNetwork settings and templates configuration.
* Example of use in a GXP tool to insert a new metadata.
Merge branch '85848-GeoNetwork_integration_first_version' into 86870-gn_integration_01
Help panel and tool integration #86870
Merge branch 'master' into 86870-gn_integration_01
Merge branch 'master' into 86870-gn_integration_01
Merge branch 'master' into 86870-gn_integration_01
Geonetwork integration first implementation.

* Adds dummy widget to make layer public #87022
* Project EPSG:3857 definition added to utmDefinitions.js #86209
Merge pull request #229 from alediator/86870-gn_integration_01

86870 gn integration 01