Support symlinks as configuration files

[bokub]

• [x] I've run a search on the existing enhancements to make sure I'm not filing a duplicate (you can use the search box at the top left corner)
• [x] I've read the Regolith documentation and didn't find any relevant topic
• [ ] I tried asking on Slack (especially for configuration related issues)

Is your feature request related to a problem? Please describe.

Hello, I tried to create a symlink of my personal configuration file in ~/.config/regolith2/i3/config but Regolith doesn't read it. It works only when I create a real copy.

Describe the solution you'd like

I would expect symlinks to config files to be supported. This worked in Regolith 1.6 by the way.

Thank you very much !