Perf: remove version from nodes

[arriqaaq]

Description

Inserts are extremely slow because on every insert the version has to be updated across all the higher nodes which is not really necessary.

main:

seq_insert/vart         time:   [1.0669 µs 1.0857 µs 1.1037 µs]
                        thrpt:  [906.07 Kelem/s 921.08 Kelem/s 937.26 Kelem/s]

seq_insert_mut/vart     time:   [298.19 ns 304.07 ns 313.97 ns]
                        thrpt:  [3.1850 Melem/s 3.2888 Melem/s 3.3536 Melem/s]

rand_insert/vart        time:   [1.2074 µs 1.2355 µs 1.2623 µs]
                        thrpt:  [792.20 Kelem/s 809.38 Kelem/s 828.26 Kelem/s]

rand_insert_mut/vart    time:   [435.92 ns 447.12 ns 460.86 ns]
                        thrpt:  [2.1699 Melem/s 2.2365 Melem/s 2.2940 Melem/s]

seq_delete/vart         time:   [1.1476 µs 1.1649 µs 1.1792 µs]
                        thrpt:  [848.06 Kelem/s 858.41 Kelem/s 871.36 Kelem/s]

rand_delete/vart        time:   [897.98 ns 944.47 ns 1.0036 µs]
                        thrpt:  [996.42 Kelem/s 1.0588 Melem/s 1.1136 Melem/s]

perf/remove-version-from-node

seq_insert/vart         time:   [932.63 ns 939.54 ns 945.09 ns]
                        thrpt:  [1.0581 Melem/s 1.0644 Melem/s 1.0722 Melem/s]

seq_insert_mut/vart     time:   [130.66 ns 132.52 ns 135.70 ns]
                        thrpt:  [7.3693 Melem/s 7.5459 Melem/s 7.6537 Melem/s]

rand_insert/vart        time:   [1.1020 µs 1.1271 µs 1.1520 µs]
                        thrpt:  [868.04 Kelem/s 887.25 Kelem/s 907.47 Kelem/s]

rand_insert_mut/vart    time:   [287.29 ns 298.70 ns 311.83 ns]
                        thrpt:  [3.2068 Melem/s 3.3478 Melem/s 3.4808 Melem/s]

seq_delete/vart         time:   [884.48 ns 895.39 ns 904.39 ns]
                        thrpt:  [1.1057 Melem/s 1.1168 Melem/s 1.1306 Melem/s]

rand_delete/vart        time:   [533.20 ns 566.94 ns 610.14 ns]
                        thrpt:  [1.6390 Melem/s 1.7639 Melem/s 1.8755 Melem/s]