This new implementation allows for expanding any environment variable so
it is not limited to just `~`, `$HOME`, `$Env:USERPROFILE` and
`$Env:KOMOREBI_CONFIG_HOME`.
It expands the follwing formats:
- CMD: `%variable%`
- PowerShell: `$Env:variable`
- Bash: `$variable`
I searched throughout the code base for path and migrate any code that
might need to PathExt::replace_env.
It is possible that I might have missed a few places due to my
unfamiliarity with the code base, so if you find any, please let me
know.
Most of the paths that needed this trait, are in:
- Clap arguments, and that was handled by #[value_parse] attribute and a
helper function.
- SocketMessage and that was handled by custom deserialization with the
help of serde_with crate
