Enhance VCF output

[apriha]

Several updates from Sano Genetics to enhance VCF output:

• Support VCF v4.3
• Ensure contig ID matches CHROM value
• Correctly populate null values for haploid chromosomes
• Handle reading and writing VCFs with imprecise indels
• Add several meta-information fields:
  • detectedCompany
  • detectedOriginalBuild
  • detectedSex
  • detectedChip

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 84.21053% with 12 lines in your changes missing coverage. Please review.

Project coverage is 93.38%. Comparing base (28146f8) to head (eaf5824). Report is 12 commits behind head on master.

Files	Patch %	Lines
src/snps/io/writer.py	78.18%	5 Missing and 7 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #184 +/- ## ========================================== + Coverage 92.47% 93.38% +0.91% ========================================== Files 8 9 +1 Lines 1753 1815 +62 Branches 395 417 +22 ========================================== + Hits 1621 1695 +74 + Misses 84 66 -18 - Partials 48 54 +6 ```

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