Feature/open ai api improvements

[mirakst]

• Switched out OpenAiLlmClient implementation to use (unofficial) OpenAI package from nuget
• Added the option to stream OpenAI API responses
• Preserved ability to mock responses
• Improved general stability of campaign page
• Added component for displaying OpenAiGptMessages
• Deleted any traces of original API testing page and food waste API client

Could re-add old OpenAiLlmClient and still use it for non-streamed requests. However, the nuget package works fine as well and I was able to do everything with it that I found necessary.

All files except ChatRPG.csproj are relevant for review.
This pull request closes #23

[KarmaKamikaze]

Ser skide godt ud, Mikkel! Jeg har ikke lige kunne teste flowet ift. streaming af text fra APIen, men jeg har lagt lidt comments i mellemtiden.

[damniko]

Har kun suggestions

[KarmaKamikaze]

Efter var er blevet yeetet er der kommet en smule build warnings, som lige bør fixes inden merge.

[KarmaKamikaze]

Godt arbejde!