Move the to_timestamp* functions to datafusion-functions #23810

Job	Run time
cargo check	9m 44s
cargo test (macos)	26m 25s
Check cargo fmt	37s
cargo test (macos-aarch64)	14m 28s
Verify MSRV (Min Supported Rust Version)	7m 22s
build with wasm-pack	2m 12s
Verify Vendored Code	47s
cargo test (win64)	40m 44s
cargo test (amd64)	10m 48s
cargo test datafusion-cli (amd64)	3m 36s
clippy	6m 5s
cargo doc	4m 23s
cargo test doc (amd64)	12m 57s
cargo test hash collisions (amd64)	10m 49s
cargo examples (amd64)	10m 26s
Run sqllogictest with Postgres runner	3m 19s
cargo test pyarrow (amd64)	2m 46s
verify benchmark results (amd64)	10m 18s
check Cargo.toml formatting	2m 52s
check configs.md is up-to-date	2m 50s
	3h 3m 28s

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