can create the directory for the customized cni conf and remove the cni conf file in cleanup command

[sofat1989]

Usually we will write the customized cni conf file and write it into the directory /etc/cni/net.d in the host. For example,

- mountPath: /host/etc/cni/net.d
          name: etc-cni-netd

- hostPath:
          path: /etc/cni/net.d
          type: DirectoryOrCreate
        name: etc-cni-netd

So the value of write-cni-conf-when-ready is /host/etc/cni/net.d/xxx-cilium.conf.
In the cleanup command, it will not remove this file.

And sometimes we need to specify write-cni-conf-when-ready to any pathes, and the directory may not exist. So the writing cni file will fail.

The commit is to solve these two issues above.

can create the directory for the customized cni conf and remove the cni conf file in cleanup command

[gandro]

cc @squeed as our resident CNI configuration file expert

[asauber]

The general idea here LGTM, and this does look necessary, given that we have a config option for the path.

A better release note would be:

create directory for custom CNI config path on startup
remove custom CNI config file with cilium cleanup command

[gandro]

Helm looks good to me. I'll defer the logic changes to the other reviewers

[gandro]

/test