Small change to use _self value as id when retrieving a resource.

[crisely09]

This is a veeeery simple approach that achieves the desired behavior in #270

Unit tests are missing at the moment.

[codecov-commenter]

Codecov Report

Merging #271 (6dcfeea) into master (1f23719) will decrease coverage by 0.20%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #271      +/-   ##
==========================================
- Coverage   72.87%   72.67%   -0.20%     
==========================================
  Files          88       88              
  Lines        5607     5622      +15     
==========================================
  Hits         4086     4086              
- Misses       1521     1536      +15     

Flag	Coverage Δ
unittests	72.67% <0.00%> (-0.20%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
kgentitylinkingsklearn/entity_linking_sklearn.py	0.00% <0.00%> (ø)
kgforge/specializations/stores/bluebrain_nexus.py	21.73% <0.00%> (-0.70%)	⬇️