Support for environment variables substitution in scripts

[SamoylovMD]

Currently Rye doesn't support environment variables in scripts:

[tool.rye.scripts]
test_env = "echo $HOME"

What I expect:

$ rye run test_env
/home/username

But what I got instead is:

$ rye run test_env
$HOME

I think this would be a good addition to the current capabilities of scripting.

[my1e5]

Duplicate of #695