support configuring experiments in workspace settings (microsoft#23267)

fixes microsoft#23241

Author: DetachHead

package.json

@@ -427,7 +427,7 @@
                 "python.experiments.enabled": {
                     "default": true,
                     "description": "%python.experiments.enabled.description%",
-                    "scope": "machine",
+                    "scope": "window",
                     "type": "boolean"
                 },
                 "python.experiments.optInto": {
@@ -457,7 +457,7 @@
                             "%python.experiments.pythonRunREPL.description%"
                         ]
                     },
-                    "scope": "machine",
+                    "scope": "window",
                     "type": "array",
                     "uniqueItems": true
                 },
@@ -486,7 +486,7 @@
                             "%python.experiments.pythonRunREPL.description%"
                         ]
                     },
-                    "scope": "machine",
+                    "scope": "window",
                     "type": "array",
                     "uniqueItems": true
                 },