Move documentation from /docs into root /

[fityannugroho]

PR Checklist

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• The commit message follows our Contributing Guidelines
• Tests for the changes have been added (optional, for bug fixes or features)
• Docs have been added / updated (optional, for bug fixes or features)

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What kind of change does this PR introduce?

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• Bug fix
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What is the current behavior?

Please describe the current behavior that you are modifying, or link to a relevant issue.

Issue Number: N/A

Move the documentation to the root to make it more accessible.

What is the new behavior?

This pull request includes several changes to the API's base route and health check, as well as updates to the API documentation and tests. The most important changes include the removal of the base route endpoint, modification of the API documentation path, and updates to the test cases.

Removal of base route endpoint:

• src/app.controller.ts: Removed the base route endpoint and its associated ApiOperation and ApiOkResponse decorators.

Modification of API documentation path:

• src/main.ts: Changed the API documentation path from /docs to /.

Updates to test cases:

• test/app.e2e-spec.ts: Replaced the test case for the base route (/) with a test case for the health check endpoint (/health).

Other information

This is BREAKING CHANGES