Avoid conflict if two files have same base name

[itowlson]

Not sure how we can do this, but if you have two files with the same (base) name e.g. foo.rego and policy/foo.rego and deploy both then they will end up overwriting each other's configmap, even if they have different contents.

Perhaps we should key the config map off the full relative file path (though this would be nasty for folks using the policy directory convention), or use the package/rule name, though this would be fiddly.

Anyway, the current 'tromple over each other' behaviour is not great.