Architecture diagram is too small

[YanisaHS]

Relevant page: https://prometheus.io/docs/introduction/overview/

The diagram in the Architecture section is too small and unreadable. This is how it appears on my screen:

There's also no option to expand it.

[dykderrick]

It happens across various image assets on the website. Another example is https://prometheus.io/docs/guides/cadvisor/#exploring-metrics-in-the-expression-browser

Source code example:

https://github.com/prometheus/docs/blob/main/content/docs/guides/cadvisor.md?plain=1#L102-L108

I am proposing to update static image declaration from markdown style to HTML style so that we can adjust image size accordingly.