Configuration: Create a centralized configuration file

> Please read the [`CONTRIBUTING.md`](https://github.com/ComputerSocietyVITC/hms-frontend/blob/master/CONTRIBUTING.md) file before contributing and taking on this issue. **It is mandatory.**

Create a configuration file in `config.js` at the root location of the directory.

It should contain all the configuration of the project:

It should look something like this:

```js
const constants = {
colors: {
black: '#1E1E1E',
white: '#F5F5F5',
// ... more colors
},
text: {
logo: 'Logo',
heroHeading: 'Hero Heading',
heroSubheading: 'Hero Subheading',
// ... more text variables
},
};

export default constants;
```