[BUG] web-UI does not reflect changes after first show-preview

[aceisace]

Describe the bug
The current web -ui does not reflect any changes in both the show-preview button as well as the generate settings.json file. This is because both functions rely on the form submit function and a form may only be submitted once. Any changes after the first submit simply get lost, causing some confusion for users. This can be fixed by relying on AJAX for the show-preview function while the generate settings.json button remains unchanged. For this, it is necessary to update the web-ui.

To Reproduce
Steps to reproduce the behaviour:

1. Head to the web-ui
2. Insert some details
3. Click on show preview
4. Modify some more details
5. Click on show preview again

Expected behaviour
Expect the web-ui to reflect changes multiple times, regardless of how many times the show-preview button was triggered

Additional context

• This is also a good chance to use recaptcha to prevent bots on submitting the form and for the show preview
• Local paths must all be blocked, only URL calls may be made