[docs] Explain "deploying" the indexer in the quickstart

[dmihal]

In the quickstart section of the indexer docs, one heading describes deploying the indexer:

2.4 Deploying our indexer At this point, we have a brand new indexer that will index some blocks and transactions. And with both our database and Fuel indexer services up and running, all that's left to do is to build and deploy the indexer in order to see it in action. Let's build and deploy our indexer:

However, it never explains what "deploying" means, I might assume this means deploying to a remote server (similar to the graph), although I assume it's actually just deploying to my local node.

Would be helpful to have some explanations here.