gcloud-*: add pages (#11625)

* gcloud-*: add pages

---------

Signed-off-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>
Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>
Co-authored-by: Sebastiaan Speck <12570668+sebastiaanspeck@users.noreply.github.com>
Co-authored-by: Starbeamrainbowlabs <sbrl@starbeamrainbowlabs.com>

pages/common/gcloud-app.md

@@ -0,0 +1,25 @@
+# gcloud app
+
+> Build scalable applications on a managed serverless platform.
+> See also: `gcloud`.
+> More information: <https://cloud.google.com/sdk/gcloud/reference/app>.
+
+- Deploy an app's code and configuration to the App Engine server:
+
+`gcloud app deploy {{deployables}}`
+
+- List all versions of all services deployed to the App Engine server:
+
+`gcloud app versions list`
+
+- Open the current app in a web browser:
+
+`gcloud app browse`
+
+- Create an App Engine app within the current project:
+
+`gcloud app create`
+
+- Display the latest App Engine app logs:
+
+`gcloud app logs read`