This allows to infer names of options from their names in a configuration. CamelCase is translated into snake_case automatically when `apply` is triggered.
* Don't have all `RuleConfiguration`s conform to `InlinableOptionType`. Mark types that must have this capability explicitly. Same for `AcceptableByConfigurationElement`.
* A type being an `InlinableOptionType` doesn't mean it's automatically inlined. This also doesn't depend on the fact of having a name for its key configured any longer. Instead, an `inline` attribute must explicitly be set to `true` in `@ConfigurationElement`.
* Key name inference is optional and can be overwritten by specifying a key name in the attribute.
* Inlined configurations only fail in `apply` when they are really sure that something is odd. Otherwise, they accept to not being updated.
Danny Mösch