Add strict and clear guidelines for the usage of UI Framework

### Description
Add strict guidelines for usage of Semantic-UI which is the UI framework decided for this project.

### Guidelines can contain the following lines

1. Codes of UI components should use the Semantic-UI classes.
2. If there is a need of creating some custom component, it can be customized using Semantic-UI (Instruction for such are included in [theming in semantic-UI](https://semantic-ui.com/usage/theming.html#composing-a-component) by composing a custom component. Such efforts are appreciated as these components can be reused in other parts of the app.
3. Contributors try to minimize the usage of custom CSS and use Semantic-UI predefined classes.