Add charts to variantdata

[EddieLF]

Displays charts on the VariantData page with react, using chart.js and the wrapper react-chartjs-2 and antd for in tabs. See https://github.com/populationgenomics/variant-curation-portal/pull/61 for the four new fields added recently.

The Genotype Qualities can take a value from 1-100 and these are binned into bars of width 5.

The Read Depths can take a value from 1-N and are binned into bars of width 5 also.

The Allele Balances are calculated from the Allelic Depth array [[REF,ALT], [REF,ALT], ..., [REF,ALT]], where each balance is AB=ALT/(REF+ALT). These take values in the range [0, 1.0] and are binned into bars of width 0.05.

The null handling means that for older variants without these fields populated, nothing will be shown on the charts.

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Please see this video for a demo of the new charts: Google Drive Link to Screen Recording

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This is in an effort to recreate the charts provided by GnomAD, such as this one:

[cassimons]

LGTM. Can you add a couple of screen grabs showing what the final result looks like?

[EddieLF]

@cassimons

For a random variant:

Genotype qualities: [99, 99]

Read Depths: [76, 52]

Allelic Balances: [0.37, 0.56] (from Allelic Depths: [[48, 28], [23, 29]])

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For a random variant with no values for GQ_all, DP_all, AD_all, the charts are empty:

[cassimons]

I am happy with this, @illusional can you pls approve if/when you give the 👍 ?