Deprecate DeploymentConfigs in 4.14

Epic Goal*

Deprecate DeploymentConfigs and strongly recommend customers to migrate to Deployments
 
Why is this important? (mandatory)

The current implementation of DeploymentConfigs is based on management of ReplicationController objects. Since development of ReplicationController has ceased and upstream recommends to use ReplicaSet objects instead, it turns out to be difficult to provide any reasonable support for development of new features or resolution of non-security and non-critical fixes. To provide the same ReplicaSet supportability the DeploymentConfigs needs to be extensively refactored. The refactoring represents a potential breaking change. Thus to avoid any portability issues caused by the refactoring the development of new features and non-essential fixes for DeploymentConfig has stopped. We strongly recommend migrating any existing DeploymentConfig workload to use Deployments.
 
Scenarios (mandatory) 

Migration of DCs into Deployments is per customer case base. Deployments provide fully compatible alternative in many use cases. In other case we need to revisit each affected customer cases to recommend a replacement.
 
Dependencies (internal and external) (mandatory)

No code changes. Only deprecation notices.

Acceptance Criteria (optional)

$ oc apply -f dc.yaml 
Warning: apps.openshift.io/v1 DeploymentConfig is deprecated in v4.14+
deploymentconfig.apps.openshift.io/recreate-example created
$ oc get dc -A
Warning: apps.openshift.io/v1 DeploymentConfig is deprecated in v4.14+
NAMESPACE   NAME               REVISION   DESIRED   CURRENT   TRIGGERED BY
default     recreate-example   1          2         2         config
$ oc rollout pause deploymentconfigs/recreate-example
Warning: apps.openshift.io/v1 DeploymentConfig is deprecated in v4.14+
deploymentconfig.apps.openshift.io/recreate-example paused

Drawbacks or Risk (optional)

The API is getting deprecated, not removed. Customers can still keep using DCs in their workloads. We have been limiting the support for no-feature and only essential fixes (critical or security).

Done - Checklist (mandatory)

The following points apply to all epics and are what the OpenShift team believes are the minimum set of criteria that epics should meet for us to consider them potentially shippable. We request that epic owners modify this list to reflect the work to be completed in order to produce something that is potentially shippable.

• CI Testing -  Basic e2e automationTests are merged and completing successfully
• Documentation - Content development is complete.
• QE - Test scenarios are written and executed successfully.
• Technical Enablement - Slides are complete (if requested by PLM)
• Engineering Stories Merged
• All associated work items with the Epic are closed
• Epic status should be “Release Pending”