enable custom cost data

[ktehranchi]

Feature Request

Users who have their own assumptions over costs data need to have a way to modify the costs in build_cost data.

We are planning to integrate with the BRIDGES model to support their data production. I want to add an option that would make it easy to use some of their curtated data that doesn't come from the NREL ATB- specifically on long duration energy storage and hydrogen CTs

Suggested Solution

To create a standard data format that will append to the build_cost data output files

Additional Info

No response

[trevorb1]

relates to issue #360 and #407 (and maybe #446)