i#7590: Drcachesim configuration reader refactoring

[DmitrySPetrov]

• Implemented support for nested maps like
  name0 { name1 { name2 val2 } }

• Removed unnecessary class attributes

• Implemented template function get_type_name which returns
  human-readable type name. This function would be used for
  error reporting.

[abhinav92003]

When this is ready for review, please add me to the reviewers.

[derekbruening]

Is this part of adding new features or is it cleanup only? If it is cleanup to prepare for adding a new feature it would be good to file an issue on the feature and link here to help indicate the end goal. I thought we already had one filed on improving these config files to avoid having to duplicate entries: some kind of repeated entry automation. But I can't find it so we must have just talked about it and not filed it.

[DmitrySPetrov]

When this is ready for review, please add me to the reviewers.

OK, Sure, I'll do it! Thanks!

[DmitrySPetrov]

Is this part of adding new features or is it cleanup only? If it is cleanup to prepare for adding a new feature it would be good to file an issue on the feature and link here to help indicate the end goal. I thought we already had one filed on improving these config files to avoid having to duplicate entries: some kind of repeated entry automation. But I can't find it so we must have just talked about it and not filed it.

This part is code refactoring & cleanup. After this one I'll create one more PR to support cache replacement policy configuration.
If it's necessary to create new issue, please let me know.