Improve getting started documentation

[ernstleierzopf]

Task

Fixes #241

Description

Greatly shortened the getting started page, while also listing all tasks that are accomplished by the new getting_started.sh script. New Users can quickly read the page and decide on using the script for an interactive walkthrough of DetectMate. Before that users can also simply look at an example output of the script before deciding.

How Has This Been Tested?

• Manually tested with ./scripts/getting_started.sh and ./scripts/getting_started.sh -y.
• Added new GitHub workflow that runs on each pull request.

Checklist

• This Pull-Request goes to the development branch.
• I have successfully run prek locally.
• I have added tests to cover my changes.
• I have linked the issue-id to the task-description.
• I have performed a self-review of my own code.

---

^{Need help on this PR? Tag @codesmith-bot with what you need. Autofix is disabled.}