Move eval_hook to nu-cmd-base (#10146)

I moved hook to *nu_cmd_base* instead of *nu_cli* because it will enable
other developers to continue to use hook even if they decide to write
their on cli or NOT depend on nu-cli

Then they will still have the hook functionality because they can
include nu-cmd-base

crates/nu-cmd-base/src/lib.rs

@@ -1,3 +1,4 @@
 pub mod formats;
+pub mod hook;
 pub mod input_handler;
 pub mod util;