[FEATURE] allow keeping symlinks

[ibotty]

Is your feature request related to a problem? Please describe.
Some software likes to use symlinks, e.g. systemd user units, but I also like to include system configuration (/usr/share/sway/config.d/...) in my dot config. Also managing e.g. a bin directory with symlinks to a command that uses $0 would be nice.

ATM Bombadil resolves the symlinks and copies the file.

Describe the solution you'd like
I'd prefer if symlinks in the dotconfig repository would just not be touched. It might be possible to opt-out of symlink behavior with e.g.

[settings.dot]
systemd = { source = "systemd.units", target = ".config/systemd/user", keep_symlinks = true }

but I'd prefer to have a opt-in behaviour, because I found it quiet counterintuitive.

Describe alternatives you've considered
None