Improved Camel Case linter to automatically detect if upper or lower …

[rchache]

…camel should be enforced for consistency

Issue #, if available:
Users who consistently use upper camel for member shape member names will otherwise be flooded with extraneous violations that complain their names are not lower camel.

Description of changes:
With this change, we will add a new (default) mode to automatically detect whether the model uses upper or lower camel case more, and enforce that pattern.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[mtdowling]

I wonder of instead of needing to explicitly list namespaces to ignore (which is kind of breaking abstractions because this package shouldn't know about aws traits), we could instead validate services closures and potentially per/namespace?

So first we validate service closures by iterating over each service shape and use a Walker to find the closure of shapes connected to the service. We then do consistent casing on those.

Then, if we really wanted to and maybe we do this later, we could track shapes that weren't in any service closure and then validate per/namespace. That would catch things like inconsistencies across traits in a single namespace.