Add idemponent resource group command

The group command makes it simpler to ensure a resource group exists, and that it has been cleaned up when the bundle is uninstalled.

When used in any action other than uninstall, the mixin will ensure that the resource group exists.

install:
  - az:
      description: "Ensure my group exists"
      group:
        name: mygroup
        location: westus

When used in the uninstall action, the mixin ensures that the resource group is deleted.

uninstall:
  - az:
      description: "Cleanup my group"
      group:
        name: mygroup

I have also added the ignoreError functionality from the exec mixin so that custom user commands can handle errors.

~🚨 This relies on https://github.com/getporter/porter/pull/1846. Once that is merged, I'll cut a release and we can reference the release in our go.mod.~

getporter / az-mixin