Align on the usage of the relationships in the links section

[JanssenBrm]

We should clearly define and align the relationship type in the links section used for openEO and OGC Processes. This would help streamline the visualization of the record in the Algorithm Catalogue.

Currently, we are using the following. Some of them have a mixed usage:

rel	type	description
openeo-process	application/json	URL to the UDP
service	application/json	Link to the openEO backend or to the OGC API Processes endpoint
example	application/json	Example output in STAC format or used as examples for input parameters
example	applicaiton/netcdf	Example output in NetCDF
application	application/cwl+yaml	URL to CWL file
order	text/html	Link to the HTML page to order the service (custom/NoR)
license	application/pdf	Link to the license file
preview	image/png	Example screenshot of the output
documentation	text/html	Link to the technical documentation

A suggestion (open to feedback):

rel	type	description
application	application/json	URL to the UDP
application	application/cwl+yaml	URL to CWL file
service	application/json	Link to the openEO backend or to the OGC API Processes endpoint
output-example	application/json	Example output in STAC format
output-example	applicaiton/netcdf	Example output in NetCDF
input-example	applicaiton/json	Example of input parameters
preview	image/png	Preview images to use in the visualization
order	text/html	Link to the HTML page to order the service (custom/NoR)
license	application/pdf	Link to the license file
documentation	text/html	Link to the technical documentation

[JanssenBrm]

Tagging @jdries @soxofaan @p3dr0 @HerveCaumont to get your feedback on this.