Add 'kubectl set limit'

Add a way to set resource limits/requests on running pods

Ref: https://github.com/kubernetes/kubernetes/issues/21648

I squashed the commits to make rebasing easier
Change log:

- fixed a typo that caused the command to be run with kubectl set set instead of the correct kubectl set limit

- added a ResourcesWithPodTemplates to pkg/kubectl/cmd/util/factory.go
     instead of hardcoding these resources move there description all in one place

- Fixing some of the flow control in kubectl set limit

- update the help info

- changed the name of ResourcesWithPodTemplates to ResourcesWithPodSpecs to more accuratly describe what it is doing
    and changed the variable names to lower case to conform to go's variable naming convention

- changing the name of the command from 'set limit' to 'set resources'

- Adding the new file pkg/kubectl/cmd/set/set_resources.go

- changes to the test cases to reflect the change from 'kubectl set limit' to 'kubectl set resources'

- comment removed

- adding the man page to the git repository attempting to fix Jenkins tests

- adding the user guide

- fixed a few typos

- typo in hack/cmd-test.sh

- implamenting suggestions for command help text

- adding the dry-run flag

- removing the "remove" option in favor of zeroing out request/limits in order to remove them

- changed limits/requests to requests/limit

- changing ResourcesWithPodSpec

- updated generated docs and removed whitespace

- change priint on success message from "resource limits/requests updated" to "resource requirements updated"

- minor rebasing issues - 'hack/test-cmd.sh' now passes

- cmdutil.PrintSuccess added another argument

- fixing mungedocs failure

- removed whitespace from hack/make-rules/test-cmd.sh and an erroneous entry from pkg/cloudprovider/providers/openstack/MAINTAINERS.md

- fixed typo in Short: field of the cobra command

- rebased

- Creating a new factory in the ResourcesWithPodSpecs() so that the testing will pass

- changing ResourcesWithPodSpecs, it doesn't need to be a method of factory

docs/man/man1/kubectl-set-resources.1

@@ -0,0 +1,3 @@
+This file is autogenerated, but we've stopped checking such files into the
+repository to reduce the need for rebases. Please run hack/generate-docs.sh to
+populate this file.

docs/user-guide/kubectl/kubectl_set_resources.md

@@ -0,0 +1,36 @@
+<!-- BEGIN MUNGE: UNVERSIONED_WARNING -->
+
+<!-- BEGIN STRIP_FOR_RELEASE -->
+
+<img src="http://kubernetes.io/kubernetes/img/warning.png" alt="WARNING"
+     width="25" height="25">
+<img src="http://kubernetes.io/kubernetes/img/warning.png" alt="WARNING"
+     width="25" height="25">
+<img src="http://kubernetes.io/kubernetes/img/warning.png" alt="WARNING"
+     width="25" height="25">
+<img src="http://kubernetes.io/kubernetes/img/warning.png" alt="WARNING"
+     width="25" height="25">
+<img src="http://kubernetes.io/kubernetes/img/warning.png" alt="WARNING"
+     width="25" height="25">
+
+<h2>PLEASE NOTE: This document applies to the HEAD of the source tree</h2>
+
+If you are using a released version of Kubernetes, you should
+refer to the docs that go with that version.
+
+Documentation for other releases can be found at
+[releases.k8s.io](http://releases.k8s.io).
+</strong>
+--
+
+<!-- END STRIP_FOR_RELEASE -->
+
+<!-- END MUNGE: UNVERSIONED_WARNING -->
+
+This file is autogenerated, but we've stopped checking such files into the
+repository to reduce the need for rebases. Please run hack/generate-docs.sh to
+populate this file.
+
+<!-- BEGIN MUNGE: GENERATED_ANALYTICS -->
+[![Analytics](https://kubernetes-site.appspot.com/UA-36037335-10/GitHub/docs/user-guide/kubectl/kubectl_set_resources.md?pixel)]()
+<!-- END MUNGE: GENERATED_ANALYTICS -->