[CLI] Support programatic configuration

[dambaron]

Currently the CLI is configured through the figma.config.json file.

It would be nice to support other config files formats like:

• figma.config.js
• figma.config.cjs
• figma.config.mjs
• figma.config.ts
• figma.config.mts

Doing so could bring benefits like

• Config validation by the IDE (if types are exposed)
• Export node URL substitutions as constants and import them into the mapping files.
• ...

[tweightman-figma]

Hi @dambaron. Thanks for this. I'll create an internal task for us to track it as a feature request.