add cli.md for postgresql (Azure#8492)

* add cli.md for postgresql

* remove  and update description

specification/postgresql/resource-manager/readme.cli.md

@@ -0,0 +1,44 @@
+## CLI
+
+These settings don't need to apply `--cli` on the command line.
+
+``` yaml
+cli:
+  cli-name: postgresql
+  package-name: azure-mgmt-rdbms-postgresql
+  namespace: azure.mgmt.rdbms.postgresql
+  test-scenario:
+    - name: Create a new server
+    - name: Create a server as a geo restore
+    - name: Create a replica server
+    - name: Create a database as a point in time restore
+    - name: DatabaseCreate
+    - name: FirewallRuleCreate
+    - name: ConfigurationCreateOrUpdate
+    - name: Create or update a virtual network rule
+    - name: Update a server's threat detection policy with all parameters
+    - name: Update a server's threat detection policy with minimal parameters
+    - name: Get a server's threat detection policy
+    - name: Gets a virtual network rule
+    - name: ConfigurationGet
+    - name: FirewallRuleGet
+    - name: DatabaseGet
+    - name: List virtual network rules
+    - name: ConfigurationList
+    - name: FirewallRuleList
+    - name: DatabaseList
+    - name: LogFileList
+    - name: ReplicasListByServer
+    - name: ServerGet
+    - name: PerformanceTiersList
+    - name: ServerListByResourceGroup
+    - name: ServerList
+    - name: OperationList
+    - name: ServerRestart
+    - name: ServerUpdate
+    - name: NameAvailability
+    - name: Delete a virtual network rule
+    - name: FirewallRuleDelete
+    - name: DatabaseDelete
+    - name: ServerDelete
+```