feat(hugr-py): builder for function definition/declaration and call (… #1051

Job	Run time
Check for changes in Rust files	3s
check	50s
Build benchmarks 🏋️	4m 50s
tests (Rust 1.75)	1m 29s
tests (Rust stable, all features)	59s
tests (Rust beta)	1m 31s
tests (Rust stable, no features)	1m 1s
tests (Rust nightly)	1m 20s
Required checks 🦀	1s
coverage	2m 44s
	14m 48s

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