chore: remove prefilter, stand-alone-test and default feature (#505) * chore: remove prefilter, stand-alone-test and default feature Signed-off-by: usamoi <usamoi@outlook.com> * fix: simplify hnsw entry Signed-off-by: usamoi <usamoi@outlook.com> --------- Signed-off-by: usamoi <usamoi@outlook.com>