Migrate Fileoutput and viewlayer management ops from gp_render

Better overall UI.
Split file output in a separate panel

operators/viewlayer_management.py

@@ -0,0 +1,54 @@
+import bpy
+
+from bpy.types import Operator
+from bpy.props import (StringProperty,
+                       BoolProperty,
+                       )
+
+class RT_OT_enable_all_viewlayers(Operator):
+    bl_idname = "rt.enable_all_viewlayers"
+    bl_label = "Enable All Viewlayers"
+    bl_description = "Enable all View layers except those named 'exclude'" # 'View Layer'
+    bl_options = {"REGISTER"}
+
+    def execute(self, context):
+        scn = context.scene
+
+        vl_list = [vl for vl in scn.view_layers if not vl.use and vl.name not in {'exclude',}] # 'View Layer',
+        for v in vl_list:
+            v.use = True
+
+        self.report({"INFO"}, f'{len(vl_list)} ViewLayers Reactivated')
+        return {"FINISHED"}
+
+class RT_OT_activate_only_selected_layers(Operator):
+    bl_idname = "rt.activate_only_selected_layers"
+    bl_label = "Activate Only Selected Layers"
+    bl_description = "Activate only selected node view layer , excluding all others"
+    bl_options = {"REGISTER"}
+
+    def execute(self, context):
+        scn = context.scene
+
+        nodes = scn.node_tree.nodes
+
+        rlayers_nodes = [n for n in nodes if n.select and n.type == 'R_LAYERS']
+        vls = [scn.view_layers.get(n.layer) for n in rlayers_nodes if scn.view_layers.get(n.layer)]
+        for v in scn.view_layers:
+            v.use = v in vls
+
+        self.report({"INFO"}, f'Now only {len(vls)} viewlayer active (/{len(scn.view_layers)})')
+        return {"FINISHED"}
+
+classes = (
+    RT_OT_enable_all_viewlayers,
+    RT_OT_activate_only_selected_layers
+)
+
+def register():
+    for cls in classes:
+        bpy.utils.register_class(cls)
+
+def unregister():
+    for cls in reversed(classes):
+        bpy.utils.unregister_class(cls)