Allow setting of additional labels for services

[sebidude]

This PR enables users to set labels on all services.

[zyyw]

@sebidude , thank you for the contribution to harbor-helm! Could you please justify a little bit why you would like to allow setting of additional labels for services?
Thanks again.

[sebidude]

It will enable us to automatically configure external loadbalancers where their controller needs certain labels in the services.
For us, it would have been enough to just set the labels on the harbor service, but for filtering in logs and metrics, it can also come handy to have labels on all of them.
Let me know if you need more info on this.

[zyyw]

Thanks! @sebidude , could you please update the README.md for this configuration?

[sebidude]

Readme is updated. Let me know if you need anything else.

Thanks

[github-actions]

This PR is being marked stale due to a period of inactivty. If this PR is still relevant, please comment or remove the stale label. Otherwise, this PR will close in 30 days.

[sebidude]

What a pity. Now there are merge conflicts.