Add documentation for Quick Start Project

[devvaannsh]

This PR does the following changes :-

1. Adds documentation for Quick Start Project, along with the images. (This appears as a separate section in between 'Editing-Text' and 'Features'.
2. It sets the trailingSlash to false in docusaurus.config.js, as it was adding unnecessary slashes at the end of the file paths. This was causing issues when trying to provide the file path without the extension.
   For ex :- 'features/quickEdit' (is valid path), but because of the trailingSlash the file path became :-
   'features/quickEdit/' (invalid path)
3. Modified the way the filepaths are provided, now indexes of files are no longer needed. Thus, won't need to modify the file paths, whenever a new section is added/removed.
   (04-Features/06-quick-edit.md) [previously]
   (Features/quick-edit) [current]

[abose]

Will this break links in the existing userbase? Eg: we have doc links with a / distributed in desktop apps, and those links may end up unreachable?
https://github.com/phcode-dev/phoenix/blob/main/src/assets/default-project/en/Newly_added_features.md?plain=1

[devvaannsh]

Yes, you're right. This change might break those links.

[abose]

LGTM. Thanks for contributing @devvaannsh

Merging to test.