1st update of Kubeflow Roadmap for Kubeflow 1.6 (kubeflow#6456)

* 1st update of Kubeflow Roadmap for Kubeflow 1.6

@annajung @kimwnasptd @DomFleischmann I have created this PR as a quick way to update the Kubeflow Roadmap to include KF 1.6.   My view is that we can update this in a simple way and then add more details if needed.     Please review, improve as you see needed.   Thanks.   Jsoh

* accept anna's updates to ROADMAP.md

Co-authored-by: Anna <antheaj@vmware.com>

* Added Themes section

added Themes section and moved K8s 1.22 support to themes, removed x.y.z version details from each working group roadmap

* fixed formatting, removed version  on Notebook

fixed formatting, removed version placeholder on Notebook, removed 1.22 support statement at end of 1.6 sections (as we have added it to the Themes section)

* Added link to KFP CLI design doc

Added link to KFP CLI design doc

Co-authored-by: Anna <antheaj@vmware.com>

Author: jbottum

ROADMAP.md

@@ -1,6 +1,50 @@
 # Kubeflow Roadmap
 
-## Kubeflow 1.5 Release, Due: March 2022
+## Kubeflow 1.6 Release, Due: July 2022
+* Kubeflow 1.6 [milestones and timelines](https://github.com/kubeflow/community/pull/558)
+
+#### Themes
+* Kubernetes 1.22 support
+
+### Major Features from each Working Group (note: Individual WG versions are independent of Kubeflow's)
+
+#### Kubeflow Pipelines
+* V2 Preview: Support running pipeline in Argo-agnostic approach
+* New DAG visualization based on Pipeline Template and MLMD
+* SDK to change from `kfp.v2` to `kfp`
+* KFP SDK CLI [design](https://docs.google.com/document/d/1Z79ebKaf3hjyadSRsme1Qo7F-Tqu4qM1cyKuLeu2PgA/edit#heading=h.x9snb54sjlu9)
+
+#### Katib
+* Support for Population based training
+* Support JSON format for Metrics Collector
+* UI Enhancement to add a separate page for Trials and show Trial logs
+
+#### Training Operator
+* PyTorch elastic training enhancements
+* Elastic scheduling with Volcano support
+* MPI Operator v2
+
+#### Notebooks, Central Dashboard, Web Apps, Manifest
+* Sorting and filtering support for the web apps
+* Expose Notebook idleness information in the JWA
+
+#### KServe
+* Knative 1.0 support and certified for KServe Serverless installation
+* KServe 0.9 SDK with ModelServer API name changes and improvement for CloudEvent support
+* New ServingRuntime and ClusterServingRuntime CRDs
+* New ModelSpec in InferenceServices
+* ModelMesh updates include support for multi-namespace reconciliation
+
+#### Detailed features, bug fixes and enhancements will be identified in the Working Group Roadmaps
+
+* [Training Operators](https://github.com/kubeflow/common/blob/master/ROADMAP.md)
+* [KFServing](https://github.com/kubeflow/kfserving/blob/master/ROADMAP.md)
+* [Katib](https://github.com/kubeflow/katib/blob/master/ROADMAP.md)
+* [Kubeflow Pipelines](https://github.com/kubeflow/pipelines/blob/master/ROADMAP.md)
+* [Notebooks, Central Dashboard](https://docs.google.com/document/d/1YtSWRhdhyOgd6ZQcWLM38TGDy2H_EhXjr8U5lUi37_I/edit)
+
+
+## Kubeflow 1.5 Release, Delivered: March 2022
 * Kubeflow 1.5 [milestones and timeline](https://github.com/kubeflow/community/pull/538)
 
 ### Themes