feat: add plan modifiers for user and instance attributes in YAML configuration

stackit/internal/services/postgresflexalpha/user/planModifiers.yaml

@@ -0,0 +1,55 @@
+fields:
+  - name: 'id'
+    modifiers:
+      - 'UseStateForUnknown'
+
+  - name: 'user_id'
+    modifiers:
+      - 'UseStateForUnknown'
+
+  - name: 'instance_id'
+    validators:
+      - validate.NoSeparator
+      - validate.UUID
+    modifiers:
+      - 'UseStateForUnknown'
+
+  - name: 'project_id'
+    validators:
+      - validate.NoSeparator
+      - validate.UUID
+    modifiers:
+      - 'UseStateForUnknown'
+      - 'RequiresReplace'
+
+  - name: 'name'
+    modifiers:
+      - 'UseStateForUnknown'
+
+  - name: 'roles'
+    modifiers:
+      - 'UseStateForUnknown'
+
+  - name: 'password'
+    modifiers:
+      - 'UseStateForUnknown'
+
+  - name: 'host'
+    modifiers:
+      - 'UseStateForUnknown'
+
+  - name: 'port'
+    modifiers:
+      - 'UseStateForUnknown'
+
+  - name: 'region'
+    modifiers:
+      - 'RequiresReplace'
+
+  - name: 'status'
+    modifiers:
+      - 'UseStateForUnknown'
+
+  - name: 'connection_string'
+    modifiers:
+      - 'UseStateForUnknown'