benchmarks: add string compression benchmark #6607

Job	Run time
C++ API (coverage)	1m 7s
Rust tests (tsan)	6m 39s
Rust tests (miri)	1m 37s
Rust/C++ FFI tests (tsan)	2m 0s
Rust/C++ FFI tests (asan)	2m 10s
Rust tests (asan)	7m 1s
Mirror DuckDB to R2 / Resolve DuckDB version and check R2	8s
DuckDB libraries available in R2	3s
Mirror DuckDB to R2 / Mirror DuckDB ${{ matrix.archive }} to R2	0s
Rust tests (coverage) (tests)	6m 42s
	27m 27s

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