feat(proto): improve IPv6 column speed

[ernado]

name                     old time/op    new time/op     delta
ColIPv6_DecodeColumn-32    2.72µs ± 3%     0.49µs ± 3%   -82.08%  (p=0.008 n=5+5)
ColIPv6_EncodeColumn-32    2.27µs ± 3%     0.22µs ± 3%   -90.10%  (p=0.008 n=5+5)

name                     old speed      new speed       delta
ColIPv6_DecodeColumn-32  5.88GB/s ± 3%  32.85GB/s ± 3%  +458.15%  (p=0.008 n=5+5)
ColIPv6_EncodeColumn-32  7.04GB/s ± 3%  71.13GB/s ± 3%  +910.20%  (p=0.008 n=5+5)

With purego:

name                     old time/op    new time/op     delta
ColIPv6_DecodeColumn-32    2.74µs ± 1%     1.78µs ± 4%  -34.99%  (p=0.008 n=5+5)
ColIPv6_EncodeColumn-32    2.31µs ± 8%     1.39µs ± 1%  -39.89%  (p=0.008 n=5+5)

name                     old speed      new speed       delta
ColIPv6_DecodeColumn-32  5.85GB/s ± 1%   9.00GB/s ± 5%  +53.91%  (p=0.008 n=5+5)
ColIPv6_EncodeColumn-32  6.95GB/s ± 7%  11.54GB/s ± 1%  +66.11%  (p=0.008 n=5+5)

[codecov]

Codecov Report

Merging #17 (fd47dd1) into main (69a2fcf) will decrease coverage by 0.18%.
The diff coverage is 90.32%.

@@            Coverage Diff             @@
##             main      #17      +/-   ##
==========================================
- Coverage   79.37%   79.18%   -0.19%     
==========================================
  Files         105      105              
  Lines        4256     4233      -23     
==========================================
- Hits         3378     3352      -26     
- Misses        709      711       +2     
- Partials      169      170       +1     

Impacted Files	Coverage Δ
proto/col_ipv6_unsafe_gen.go	88.88% <88.88%> (ø)
proto/ipv6.go	100.00% <100.00%> (ø)
proto/col_ipv6_safe_gen.go

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