Add option blind/directed upper sel threshold; rename distFunc to metric

[ray6080]

Description

Allow users to config upper selectivity threshold for blind and directed searches in the query_hnsw_index function.
Renamed the option distFunc to metric.

[github-actions]

Benchmark Result

Master commit hash: 72504675482c301eea2e22e78a9071a654e4c924
Branch commit hash: e2495f112390f1af73740b5e8f758866d6aecf0a

Query Group	Query Name	Mean Time - Commit (ms)	Mean Time - Master (ms)	Diff
aggregation	q24	721.30	723.91	-2.61 (-0.36%)
aggregation	q28	6599.27	6593.26	6.00 (0.09%)
filter	q14	120.53	119.47	1.06 (0.89%)
filter	q15	117.50	112.54	4.97 (4.41%)
filter	q16	341.39	341.04	0.36 (0.10%)
filter	q17	445.18	435.40	9.79 (2.25%)
filter	q18	1995.17	1993.83	1.34 (0.07%)
filter	zonemap-node	85.33	81.83	3.50 (4.28%)
filter	zonemap-node-lhs-cast	82.77	83.03	-0.26 (-0.31%)
filter	zonemap-node-null	81.73	81.29	0.44 (0.54%)
filter	zonemap-rel	5740.40	5691.24	49.16 (0.86%)
fixed_size_expr_evaluator	q07	671.54	667.66	3.88 (0.58%)
fixed_size_expr_evaluator	q08	958.65	964.35	-5.70 (-0.59%)
fixed_size_expr_evaluator	q09	961.81	965.71	-3.90 (-0.40%)
fixed_size_expr_evaluator	q10	246.20	256.08	-9.88 (-3.86%)
fixed_size_expr_evaluator	q11	250.95	255.80	-4.85 (-1.90%)
fixed_size_expr_evaluator	q12	227.43	228.34	-0.92 (-0.40%)
fixed_size_expr_evaluator	q13	1556.22	1567.70	-11.48 (-0.73%)
fixed_size_seq_scan	q23	107.48	100.67	6.81 (6.76%)
join	q29	728.41	787.43	-59.02 (-7.49%)
join	q30	1602.69	1717.31	-114.62 (-6.67%)
join	q31	6.64	7.53	-0.89 (-11.81%)
join	SelectiveTwoHopJoin	54.74	48.18	6.57 (13.63%)
ldbc_snb_ic	q35	9.63	10.42	-0.80 (-7.65%)
ldbc_snb_ic	q36	99.14	102.04	-2.90 (-2.85%)
ldbc_snb_is	q32	2.40	2.73	-0.33 (-12.07%)
ldbc_snb_is	q33	13.92	13.01	0.91 (7.01%)
ldbc_snb_is	q34	1.23	1.24	-0.01 (-0.43%)
multi-rel	multi-rel-large-scan	1770.52	1735.99	34.53 (1.99%)
multi-rel	multi-rel-lookup	6.49	6.72	-0.23 (-3.36%)
multi-rel	multi-rel-small-scan	199.34	204.60	-5.27 (-2.57%)
order_by	q25	121.62	126.22	-4.60 (-3.64%)
order_by	q26	431.15	437.92	-6.77 (-1.55%)
order_by	q27	1368.02	1398.52	-30.50 (-2.18%)
recursive_join	recursive-join-bidirection	291.36	318.40	-27.04 (-8.49%)
recursive_join	recursive-join-dense	7169.43	7140.60	28.83 (0.40%)
recursive_join	recursive-join-path	23461.40	23833.24	-371.83 (-1.56%)
recursive_join	recursive-join-sparse	640.57	641.02	-0.45 (-0.07%)
recursive_join	recursive-join-trail	7108.09	7137.99	-29.90 (-0.42%)
scan_after_filter	q01	164.69	164.84	-0.15 (-0.09%)
scan_after_filter	q02	149.12	150.28	-1.16 (-0.77%)
shortest_path_ldbc100	q37	81.76	80.37	1.39 (1.73%)
shortest_path_ldbc100	q38	246.36	354.67	-108.31 (-30.54%)
shortest_path_ldbc100	q39	60.54	62.45	-1.92 (-3.07%)
shortest_path_ldbc100	q40	299.35	356.77	-57.43 (-16.10%)
var_size_expr_evaluator	q03	2151.66	2161.17	-9.51 (-0.44%)
var_size_expr_evaluator	q04	2304.55	2298.35	6.19 (0.27%)
var_size_expr_evaluator	q05	2669.04	2705.68	-36.64 (-1.35%)
var_size_expr_evaluator	q06	1330.29	1331.86	-1.57 (-0.12%)
var_size_seq_scan	q19	1427.48	1425.53	1.95 (0.14%)
var_size_seq_scan	q20	2672.50	2710.37	-37.88 (-1.40%)
var_size_seq_scan	q21	2231.39	2262.26	-30.87 (-1.36%)
var_size_seq_scan	q22	124.13	124.32	-0.19 (-0.15%)