feat: fail helm templating if configInline is defined

[tamcore]

This PR will prevent existing setups from destroying themselves, by raising an exception if configInline is defined.

philipp@ ~/metallb/charts/metallb (patch-2) $ helm template --namespace metallb-system metallb . --set configInline.bla.foo=hi
zsh: correct 'template' to 'templates' [nyae]? n
Error: execution error at (metallb/templates/deprecated_configInline.yaml:2:4): Starting from v0.13.0 configInline is no longer supported. Please see https://metallb.universe.tf/#backward-compatibility

Use --debug flag to render out invalid YAML
philipp@ ~/metallb/charts/metallb (patch-2) $

[fedepaol]

Thanks a lot!