Document search(), acquire() and load() in documenting-a-resource.md

[jesper-friis]

          Looks OK. It seems that search and acquire and load are not presented in the the documenting-a-resource.md. I suggest this is added as an issue to complete the documentation of the documentation.

Originally posted by @francescalb in #387 (review)

[francescalb]

search and delete are closed in 397