Name the default files clearly in web studio

# Feature request

The default files in the web studio are currently not named clearly. One is codecharta, the other codecharta_analysis. It's obvious which is which if you know the structure of CodeCharta, so this is a nitpick. Nevertheless it would help novice and intermediate users to label the clearly. It also helps in demos, because right now an explanation is needed to say that the "codecharta" file does not in fact include the "codecharta_analysis" but only includes the "codecharta_visualization"

## Description

As a novice, intermediate or demo user, I want clearly labelled files, so that I do not have to think.

## Acceptance criteria
- The files are named "codecharta_analysis" and "codecharta_visualization"
- The "web studio" button on the [landing page](https://codecharta.com/) set these new file names, so CodeCharta loads them both
- The "web studio" links in the [Readme](https://github.com/MaibornWolff/codecharta) set these new file names, so CodeCharta loads them both

Start by checking how the web studio links on the landing page and README set the default file names, then trace where those links are defined in the TypeScript web studio entry points. Update both links so the files are named codecharta_analysis and codecharta_visualization, and verify that the web studio loads both defaults.

Written by the indexing model from the issue text.