Separate and merge .h/.hpp files in duckdb #4305

Job	Run time
Rust/C++ FFI tests (asan)	2m 25s
Rust/C++ FFI tests (tsan)	2m 6s
Rust tests (miri)	1m 36s
Rust tests (asan)	6m 56s
Rust tests (tsan)	6m 26s
Mirror DuckDB to R2 / Resolve DuckDB version and check R2	5s
DuckDB libraries available in R2	3s
Mirror DuckDB to R2 / Mirror DuckDB ${{ matrix.archive }} to R2	0s
Rust tests (coverage) (tests)	6m 12s
	25m 49s

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