Case insensitive search of method names

https://bugzilla.redhat.com/show_bug.cgi?id=1134500

When searching for methods the case shouldn't be taken into account
Can you move this `arel_table` logic into `MiqAeMethod`?

e.g.:
```
aem = cls.methods_by_name(method_name)
# or
aem = ::MiqAeMethod.methods_by_case_and_name(cls.id, method_name)
```