Use regex instead of regex-lite

[01mf02]

This is an experiment, see #1274.

I evaluated jqjq with it as follows:

cd jaq
cargo build --release
git clone https://github.com/wader/jqjq
cd jqjq
git checkout 535076f3c4ede19817d5946a6d1703b04d18778a
time ../target/release/jaq -n -L . 'include "jqjq"; eval(".")'

This yields 0.921s with regex + PikeVM vs. 0.493s with regex_lite.
(For comparison, jq takes 0.499s.)

[01mf02]

This is too slow, and because regex-lite better fits jaq's philosophy, let's keep it.