Enhance/docker.md

[nifedara]

What does this PR do?

• Rearranges the configuration steps in docker.md to make it clearer
• Changes the documentation image to match the new name, raw-data-api from export-data-api

Consideration

I noticed that the configuration steps will get mixed up as the Database configuration and OSM authentication appeared to be under .env configuration approach instead of as a step of their own. (I further confirmed this when a fellow Outreachy contributor reached out to me for clarity)

How to test?

You can see the change here: docker.md