Better support for Git Clients

[acunniffe]

Many devs use Git Clients, which (when being pointed at a git binary often run a --version check and look for libexec

[svarlamov]

➜  testing-git-10 git:(master) ✗ git --exec-path

thread 'main' panicked at src/git/repository.rs:1837:52:
called `Option::unwrap()` on a `None` value
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
➜  testing-git-10 git:(master) ✗ /opt/homebrew/bin/git --exec-path
/opt/homebrew/opt/git/libexec/git-core
➜  testing-git-10 git:(master) ✗

[acunniffe]

Spoke to Sasha - move symlink logic into the install-hooks, and fix panic.
Verify if Fork uses the exec symlinks before doing a pass-through / alias wrapper

[svarlamov]

Wdyt of doing the symlink logic in rust in the install flow? Just hoping to keep complexity out of the install scripts themselves. Everything else looks great!