Allow specification of annotations for the smbshare service

[jpflouret]

Adding annotations to the created servcie would allow for additional configuration of the created service. For example, with metallb you could specify the requested address pool to use. Another use case could be specifying the hostname to use with external-dns for registering the load balancer assigned IP address with an external DNS provider (which would address #147).

I would propose that the SmbCommonConfig resource should contain an annotations key either under network or under a new different key. Perhaps serviceSettings could be a sibling of podSettings and it could contain additional settings for the service (e.g. loadBalancerIP).