Implement Rust ETL processor for JSONL to CSV conversion

[blueogin]

Usage

The program can be run in several ways:

1. Process a file and output to a file:

cargo run --release -- -i sample.jsonl -o output.csv

2. Process from STDIN and output to STDOUT:

cargo run --release

3. Process a file and output to STDOUT:

cargo run --release -- -i sample.jsonl

4. Process from STDIN and output to a file:

cargo run --release -- -o output.csv