Move Median to `functions-aggregate` and Introduce Numeric signature #27135

Job	Run time
cargo test (macos)	9m 4s
cargo check	4m 28s
build with wasm-pack	2m 24s
Check cargo fmt	32s
cargo test (macos-aarch64)	8m 34s
Verify MSRV (Min Supported Rust Version)	6m 43s
Verify Vendored Code	47s
cargo test (win64)	33m 7s
cargo test datafusion-cli (amd64)	3m 45s
cargo test (amd64)	9m 4s
check Cargo.toml formatting	2m 48s
clippy	4m 43s
check configs.md is up-to-date	2m 37s
cargo test hash collisions (amd64)	9m 1s
cargo doc	3m 11s
cargo test doc (amd64)	12m 14s
cargo examples (amd64)	10m 43s
Run sqllogictest with Postgres runner	3m 9s
cargo test pyarrow (amd64)	2m 37s
verify benchmark results (amd64)	10m 12s
	2h 19m 43s

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