Use fqdn for node names

[bpradipt]

Fixes #68

- Description of the problem which is fixed/What is the use case
Fixes failed uninstall of Kata runtime when Kata is installed on specific nodes

- What I did
Used fqdn for nodename instead of host name

- How to verify it
Build the kata-operator-daemon and push the image to registry. Thereafter modify kata-operator to use the kata-operator-daemon image and go through the install/uninstall cycle

- Description for the changelog

Use FQDN for nodename

[bpradipt]

@jensfr this scenario definitely needs a test case. Will add it post merge of #62

[jensfr]

Thank you Pradipta, lgtm!

[fidencio]

@bpradipt,

I'd like to ask one thing ... are there situations where we would need the os.Hostname()?

If not, I think we could entirely get rid of getHostName(), which is only called from getNodeName() (mind, this is not required for this PR, just ideas for the future).

[fidencio]

Anyways, this is approved already, we can keep discussing the improvements for the future, but I will not block it to get merged. :-)