bash completions for kubectl

Support pre command flags:
--api-version=
-a, --auth-path=
--certificate-authority=
--client-certificate=
--client-key=
--insecure-skip-tls-verify=
--match-server-version=
-s, --server=

And commands:
get
describe
create
update
delete

Tries to be smart about things like

kubectl get -o template  requires a template file

It also tries to accept both sigular and plural versions of all
resources.  Even though it will only complete to the plural version.
It must be some friggin bash magic that makes it not crash...

I did this:

```
    echo "__has_resource command_word=${command_word}" >> /tmp/kubectl
    for ((i=command_word; i < cword; i++)); do
        local word=${words[i]}
        echo "__has_resource word=${word} i=${i}" >> /tmp/kubectl
        if __contains_word "${word}" "${all_resources[@]}"; then
            return 0
        fi
    done
```

And got

```
_kubectl command_word=i i=1
__has_resource command_word=i
__has_resource word=kubectl i=0
__has_resource word=get i=1
__kubectl_get word=get i=1 next=2
```

So it is setting i to 0 even though command_word was "i".  With your fix we get the expected result (don't start searching from 0)

```
_kubectl command_word=1 i=1
__has_resource command_word=1
__has_resource word=get i=1
__kubectl_get word=get i=1 next=2
```