docs(scheduler): add pdb max unavailable

docs/reference/Scheduler.md

@@ -203,7 +203,8 @@ autoscaling:
                 "metadata": {}
             }
         }
-    ]
+    ],
+    "pdbMaxUnavailable": "5%",
     "autoscaling": {
       "enabled": true,
       "min": 10,
@@ -234,6 +235,7 @@ forwarders: Forwarders
 autoscaling: Autoscaling
 spec: Spec
 annotation: Map
+pdbMaxUnavailable: String
 ```
 
 - **Name**: Scheduler name. This name is unique and will be the same name used for the kubernetes namespace. It's
@@ -254,6 +256,7 @@ annotation: Map
   used by them, limits and images. More info [here](#spec).
 - **annotations**: Allows annotations for the scheduler's game room. Know more about annotations on
   Kubernetes [here](https://kubernetes.io/docs/concepts/overview/working-with-objects/annotations)
+- **pdbMaxUnavailable**: Defines the disruption budget for game rooms. Optional and defaults to 5%. Value can be defined as a string representing the % between 0 and 100, "15%", or a raw number of rooms "100".
 
 ### PortRange
 The **PortRange** is used to select a random port for a GRU between **start** and **end**.
@@ -403,4 +406,43 @@ It is represented as:
 - **name**: Name of the port. Facilitates on recognition;
 - **protocol**: Port protocol. Can be UDP, TCP or SCTP.;
 - **port**: The port exposed.
-- **hostPortRange**: The [port range](#portrange) for the port to be allocated in the host. Mutually exclusive with the port range configured in the root structure.
+- **hostPortRange**: The [port range](#portrange) for the port to be allocated in the host. Mutually exclusive with the port range configured in the root structure.
+
+#### PDB Max Unavailable
+
+A string value that defines the disruption budget of Game Rooms from a specific scheduler.
+Maestro will create a [PDB Resource](https://kubernetes.io/docs/tasks/run-application/configure-pdb/)
+to prevent evictions drastically impacting availability of the Game Rooms.
+
+By default this value is set to 5%, so at worst runtime can evit 5% of the pods. There is no way to control
+what pods will be evicted - if it prefers ready, pending, etc.
+
+The configuration can be specified with this order of precedence:
+
+1. Value specified in Scheduler's definition
+
+```json
+{
+  "pdbMaxUnavailable": "10%"
+}
+```
+
+2. Value specified in the ENV VAR:
+
+```shell
+MAESTRO_SERVICES_SCHEDULERMANAGER_DEFAULTPDBMAXUNAVAILABLE="10%"
+```
+
+3. Value specified in the [config.yaml](../../config/config.yaml):
+
+```yaml
+services:
+  schedulerManager:
+    defaultPdbMaxUnavailable: "5%"
+```
+
+4. Value specified in [code](../../internal/core/entities/pdb/pdb.go) that defaults to 5%:
+
+```go
+const DefaultPdbMaxUnavailablePercentage = "5%"
+```