* [Enhancement] refactor base data elment

* fix comment

* fix comment

* fix pop not existing key without error

* update evaluator prefix

* update docstring and comments

* update doc

* update type hint and ut for evaluator

* update doc

* fix

* support metric prefix in BaseEvaluator

* update docs

* use class attribute default_prefix

* add evaluator unittest

* update composed evaluator cfg

* add building function

* resolve comments

* resolve comments

* resolve comments

* fix evaluator doc