Update get mentor categories endpoint (public) to send category IDs

[Madhawa97]

Purpose

The purpose of this PR is to fix #82

Goals

Currently, the api/categories endpoint only returns a list of category names. The category IDs are also required during the mentor application process.

Approach

Add the category IDs to the response.
Sample response:

{
    "categories": [
        {
            "category": "Data Science",
            "id": "95ba00c0-8173-43c4-9573-6b481b4085e2"
        },
        {
            "category": "Random Category",
            "id": "fe7ca629-4f5e-440a-86cb-d54f8b98ec5f"
        },
        {
            "category": "Computer Science",
            "id": "fef68adb-e710-4d9e-8772-dc4905885088"
        }
    ],
    "message": "All Categories found"
}

Screenshots

N/A

Checklist

• This PR doesn't commit any keys, passwords, tokens, usernames, or other secrets.
• I have read and understood the development best practices guidelines ( http://bit.ly/sef-best-practices )
• My code follows the style guidelines of this project
• 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

Related PRs

Test environment

Learning

[Madhawa97]

Tests are passing locally.

[anjula-sack]

@Madhawa97 Can you add the requested changes?

[Madhawa97]

Hi @anjula-sack, Can you check now, please?
update: Tests are still passing locally

[anjula-sack]

Thank you @Madhawa97