[TRTLLM-4501] fit: AutoTuner tuning config refactor and add tuning for kernel configs.

Adding a config entry in the tuning config to define the valid candidates for each part of the configs.
* AutoTuner will loop over a search grid generated from the config combinations.
* Each config will be tuned along with the specific input profile.
* The best config will be recorded in the cache value (instead of the cache key). And it will be recovered and used in the tunable runner forward.

Other enhancements:
* Use the decorator to make the tuning config definition more natural and efficient. This is an independent enhancement.
* Allow the user to not speficy the gen_tuning_buckets or the map_to_tuning_buckets function.
* Code refactoring.

Signed-off-by: Yukun He <[email protected]>

Author: hyukn