Simplify logic in create-app.adoc and allow to define stream

The idea is to define the stream value for older versions so that people
can create apps for these versions by running the command.

docs/src/main/asciidoc/_attributes.adoc

@@ -51,4 +51,6 @@
 :vault-datasource-guide: https://quarkiverse.github.io/quarkiverse-docs/quarkus-vault/dev/vault-datasource.html
 :micrometer-registry-guide: https://quarkiverse.github.io/quarkiverse-docs/quarkus-micrometer-registry/dev/index.html
 // .
+:create-app-group-id: org.acme
+// .
 include::_attributes-local.adoc[]

docs/src/main/asciidoc/_includes/devtools/create-app.adoc

@@ -3,29 +3,27 @@
 ****
 [source,bash,subs=attributes+]
 ----
-ifdef::create-app-group-id[]
-ifdef::create-app-extensions[]
+ifdef::create-app-extensions,create-app-stream[]
 quarkus create app {create-app-group-id}:{create-app-artifact-id} \
 endif::[]
-ifndef::create-app-extensions[]
+ifndef::create-app-extensions,create-app-stream[]
 ifndef::create-app-code[]
 quarkus create app {create-app-group-id}:{create-app-artifact-id} \
 endif::[]
 ifdef::create-app-code[]
 quarkus create app {create-app-group-id}:{create-app-artifact-id}
 endif::[]
 endif::[]
-endif::[]
-ifndef::create-app-group-id[]
+ifdef::create-app-stream[]
 ifdef::create-app-extensions[]
-quarkus create app org.acme:{create-app-artifact-id} \
+    --stream={create-app-stream} \
 endif::[]
 ifndef::create-app-extensions[]
 ifndef::create-app-code[]
-quarkus create app org.acme:{create-app-artifact-id} \
+    --stream={create-app-stream} \
 endif::[]
 ifdef::create-app-code[]
-quarkus create app org.acme:{create-app-artifact-id}
+    --stream={create-app-stream}
 endif::[]
 endif::[]
 endif::[]
@@ -63,12 +61,10 @@ _For more information about how to install the Quarkus CLI and use it, please re
 [source,bash,subs=attributes+]
 ----
 mvn io.quarkus.platform:quarkus-maven-plugin:{quarkus-version}:create \
-ifdef::create-app-group-id[]
-    -DprojectGroupId={create-app-group-id} \
-endif::[]
-ifndef::create-app-group-id[]
-    -DprojectGroupId=org.acme \
+ifdef::create-app-stream[]
+    -DplatformVersion={create-app-stream} \
 endif::[]
+    -DprojectGroupId={create-app-group-id} \
 ifdef::create-app-extensions[]
     -DprojectArtifactId={create-app-artifact-id} \
 endif::[]