feat: opening search APIs for OrgUnits and Categories

[RMCampos]

Description

• Create API to get Opening Categories;
• Create API to get Org Units;

Fixes SILVA-486 and SILVA-487

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• Added unit and integration tests;
• Eyeball;
• Real requests through Swagger API;

Checklist

• I have read the CONTRIBUTING doc
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have already been accepted and merged

Further comments

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Thanks for the PR!

Any successful deployments (not always required) will be available below.

Backend: https://nr-silva-364-backend.apps.silver.devops.gov.bc.ca/actuator/health
Frontend: https://nr-silva-14-frontend.apps.silver.devops.gov.bc.ca

Once merged, code will be promoted and handed off to following workflow run.
Main Merge Workflow

[jazzgrewal]

Tested using swagger works great. Still need to have conversation with Caroline about shortening the list.