docs: Show where to find api key and endpoint information (cloud)

[Rperry2174]

Currently we've had a couple of people who would like to use Grafana cloud. While the docs show placeholders they don't give much instruction where to get the actual data to fulfull those placeholders:

for example for java these are the docs we show:

But we never tell people where to get User, Password, or URL:
https://github.com/user-attachments/assets/c8b4c4b0-a2cb-4fc8-890a-7ad4d8995d65

We should either show a video, give instructions, or direct people direcly threre