feat: Added ability to set vcftype for reading str files

[mlamkin7]

When loading a GenotypeTR class you can now specify what the type of vcf you are currently reading.

Example

genotypes = data.GenotypesTR.load('tests/data/simple_tr.vcf', vcftype='hipstr')

you can choose between

vcftype : {'auto', 'gangstr', 'advntr', 'hipstr', 'eh', 'popstr'}

[aryarm]

checks are failing because of brentp/cyvcf2#270

they should resolve themselves once cyvcf2 uploads v0.30.22 to pypi