chore(monocdk): align base namespace/package with regular build (#8368)

In order to make migrating from hyper-modular CDK to Mono-CDK easier,
align the .NET and Java base namespace/package to match the ones set on
the `@aws-cdk/core` library, as those types will be hoisted to the root
of the Mono-CDK packaging.


----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: RomainMuller

packages/monocdk-experiment/package.json

@@ -41,7 +41,8 @@
     "exclude": [
       "package-info/maturity",
       "jsii/java",
-      "jsii/python"
+      "jsii/python",
+      "jsii/dotnet"
     ]
   },
   "jsii": {
@@ -51,15 +52,15 @@
     "outdir": "dist",
     "targets": {
       "dotnet": {
-        "namespace": "Amazon.CDK.MonoCDK.Experiment",
+        "namespace": "Amazon.CDK",
         "packageId": "Amazon.CDK.MonoCDK.Experiment",
         "iconUrl": "https://raw.githubusercontent.com/aws/aws-cdk/master/logo/default-256-dark.png",
         "versionSuffix": "-devpreview",
         "signAssembly": true,
         "assemblyOriginatorKeyFile": "../../key.snk"
       },
       "java": {
-        "package": "software.amazon.awscdk.monocdkexperiment",
+        "package": "software.amazon.awscdk.core",
         "maven": {
           "groupId": "software.amazon.awscdk",
           "artifactId": "monocdk-experiment",