feat: register missing namespace

[wolf4ood]

What this PR changes/adds

Register missing namespace:

• dct
• dcat
• dspace

Why it does that

Response aligned with management catalog API

Linked Issue(s)

Closes #225

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[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 73.17%. Comparing base (2d71ca0) to head (5d26750).
Report is 67 commits behind head on main.

Files	Patch %	Lines
...atalog/api/query/FederatedCatalogApiExtension.java	0.00%	3 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #226      +/-   ##
==========================================
+ Coverage   65.43%   73.17%   +7.73%     
==========================================
  Files          25       25              
  Lines         434      574     +140     
  Branches       15       25      +10     
==========================================
+ Hits          284      420     +136     
  Misses        135      135              
- Partials       15       19       +4     

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