Rust

add ability to customize tokens in parser #98

Job	Run time
Verify MSRV (Min Supported Rust Version)	5m 4s
cargo test (macos-aarch64)	20m 5s
Check cargo fmt	1m 20s
linux build test	5m 11s
Verify Vendored Code	1m 28s
build and run with wasm-pack	5m 10s
cargo check datafusion-proto features	4m 32s
cargo check datafusion features	12m 20s
cargo doc	5m 19s
verify benchmark results (amd64)	10m 28s
cargo check datafusion-functions features	2m 40s
cargo check datafusion-common features	2m 8s
cargo test (amd64)	11m 39s
cargo test doc (amd64)	8m 40s
cargo check datafusion-substrait features	10m 18s
cargo test datafusion-cli (amd64)	4m 24s
cargo examples (amd64)	12m 4s
check configs.md and ***_functions.md is up-to-date	5m 25s
clippy	5m 45s
check example README is up-to-date	46s
Run sqllogictest with Postgres runner	6m 36s
Run sqllogictest in Substrait round-trip mode	7m 3s
check Cargo.toml formatting	3m 35s
	2h 32m 0s

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