fix: add graceful shutdown and hikari connection pool

[RMCampos]

Description

• Get Hikari Connection Pool back;
• Add graceful shutdown feature.
• Remove spring devtools (locally autorestart feature, that may keep connections alive)

Closes #273

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Tested locally, all configs working properly.

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

---

Thanks for the PR!

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

Backend: https://nr-silva-274-backend.apps.silver.devops.gov.bc.ca/actuator/health
Frontend: https://nr-silva-24-frontend.apps.silver.devops.gov.bc.ca

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

---

Thanks for the PR!

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

Backend: https://nr-silva-274-backend.apps.silver.devops.gov.bc.ca/actuator/health
Frontend: https://nr-silva-24-frontend.apps.silver.devops.gov.bc.ca

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

[DerekRoberts]

Much needed. :)