Replace DynVarBinBuilder with a generic VarBinBuilder #6621

Job	Run time
Rust tests (miri)	1m 36s
Rust tests (asan)	7m 0s
Rust/C++ FFI tests (tsan)	1m 56s
Rust tests (tsan)	6m 35s
C++ API (coverage)	1m 9s
Rust/C++ FFI tests (asan)	2m 9s
Mirror DuckDB to R2 / Resolve DuckDB version and check R2	5s
DuckDB libraries available in R2	2s
Mirror DuckDB to R2 / Mirror DuckDB ${{ matrix.archive }} to R2	0s
Rust tests (coverage) (tests)	6m 53s
	27m 25s

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