Profiler validation for Composed Metrics

[pmbrull]

Feature
Based on #2845

Describe the task
Composed Metrics are based on +1 other metrics. E.g., based on the count and null_count of a column, we can obtain the null_ratio.

When building a profiler, we should validate during init that there are all the ingredients ready to compute the desired composed metrics. This means:

• Adding an abstractmethod in the ComposedMetric class to inform the ingredients
• Add a validation step when creating a profiler