Improved UI Component for the Extension

[MinuraPunchihewa]

This PR improves the UI component of the extension through the following:

1. The loading screen of the UI is integrated more neatly into the App component allowing for more readability and extensibility.
2. The Docker build process uses a more robust multi-stage build, which allows for a custom back-end to be developed as well (this back-end component is probably going to be required to resolve the issue of exposed ports).
3. Removed files rendered unnecessary as a result of the refactor such as index.js, which allows for a cleaner directory structure.
4. The path that the code re-directs to has been updated to the /editor route to avoid any complications such as what has been reported here and also possibly the reason for this (it is not entirely clear if the reason for this problem is due to the missing route as the extension seems to be working fine at the moment, but it is likely).

The changes made above are also in line with the best practices outlined by Docker for creating extensions.

[MinuraPunchihewa]

@ZoranPandovski In addition to the changes you requested, I have made a few other small changes after you review including,

• Exposing the MongoDB (47336) port
• Changing the base image used for the last stage of the build to alpine
• Removing an unnecessary build script
• Adding a CHANGELOG