Add 2 fuzzers for nu-path, nu-parser (#10376)

# Description

This PR adds a fuzzer for the nu-path and the nu-parser crate.
Now you can go to `crates/nu-path/fuzz`/`crates/nu-parser/fuzz` and run `cargo fuzz` to
find crashes.
https://github.com/nushell/nushell/issues/10365 and #9417 was found by
this


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Co-authored-by: sholderbach <sholderbach@users.noreply.github.com>

crates/nu-parser/fuzz/README.md

@@ -0,0 +1,9 @@
+# Fuzzer for `nu-parser`
+
+- For detailed info, please look at [cargo-fuzz](https://github.com/rust-fuzz/cargo-fuzz)
+
+# Quick start guide
+- Install cargo-fuzz by `cargo install cargo-fuzz`
+- Run `gather_seeds.nu` for preparing the initial seeds corpus
+- Make output directory `mkdir out`
+- Run the fuzzer with `cargo fuzz run parse out seeds`