Add necessary kubernetes template files for kubernetes-sigs move

[christianang]

This PR adds the necessary template files from https://github.com/kubernetes/kubernetes-template-project for the move to kubernetes-sigs.

There are probably a few areas that can be fleshed out more that haven't been yet. Here are some things in no particular order:

• For the contributing.md it was left fairly vanilla from the template file, except I added a contributing a patch section taken from the cluster-api-provider-vsphere contributing.md.
• For the Owners Alias, it currently only has @schrej, but we could add some/all of the VMware based contributors we have on our team (@tylerschultz @adobley @flawedmatrix and @christianang). Wasn't sure if it was better to do it before or after the move so I left it as is. Same with the Security Contacts file.
• For the readme II added the Community, discussion, contribution, and support section, but it doesn't link to any specific cluster-api-ipam-provider-in-cluster specific slack or mailing list yet. Not sure what the process there is, but maybe that can be figured out later?

Relates to #110

[schrej]

We definitely need more than one reviewer and approver. I'd be happy to have all mentioned contributors as approvers, and probably @tylerschultz and @srm09 as approvers.

Before anyone can get added as approver or reviewer, they'll need to join the kubernetes-sigs org. We can potentially sort that out post-move if pre-move contributions to this repo count.

[schrej]

Let's get this in now though, since it's the last step before opening an issue to transfer the repository. We can update reviewers, approvers and security contacts later.