[server] Add a notice that minio is only for getting started (#1299)

From our Discord, someone commented

> if minio's cautions about Single-Node, Single-Drive are to be taken
seriously:
>
> "SNSD deployments use a zero-parity erasure coded backend that
provides no
added reliability or availability beyond what the underlying storage
volume
  implements. These deployments are best suited for local testing and
evaluation, or for small-scale data workloads that do not have
availability or
  performance requirements."

MinIO was never meant as a production replacement, it was only to make
it easy
for people to get started. So add a notice in the docs re this.

server/README.md

@@ -97,7 +97,7 @@ Overall, there are [three approaches](RUNNING.md) you can take:
 * Run without Docker
 
 Everything that you might needed to run museum is all in here, since this is the
-setup we ourselves use in production.
+code we ourselves use in production.
 
 > [!TIP]
 >

server/RUNNING.md

@@ -44,6 +44,12 @@ Or interact with the MinIO S3 API
 
 Or open the MinIO dashboard at <http://localhost:3201> (user: test/password: testtest).
 
+> [!NOTE]
+>
+> While we've provided a MinIO based Docker compose file to make it easy for
+> people to get started, if you're running it in production we recommend using
+> an external S3.
+
 > [!NOTE]
 >
 > If something seems amiss, ensure that Docker has read access to the parent