Theming compatible, small UI fixes, request body fix

[meijey]

Hi,
thanks for updating the swagger generator. Wanted to do it by myself some times, but other projects had more priority ._.

I have some fixes, some are still from the old main version.

Theming compatible:

• Uses now the NR color coding (var(--red-....) instead of fix colors

UI fixes:

• removed some styles and set them to a class (if used more than once)
• fixed label / input field lengths

Full URL for the swagger-ui-tab:

• Your relative URL did not use RED.settings.httpNodeRoot. Therefore the URL could be wrong. Based now on the working original code.

Request body:

• "GET", "HEAD" and "DELETE" can have a request body but should be avoided -> openApi specs
• Therefor I added a warning to the tab if it is one of those methods and remove the request body from the created file if not set. (As this would also cause an invalid warning in the swagger-ui-tab).

Best regards and have a nice day.