refactor(vep_parser): store consequence to impact score as a project config

[ireneisdoomed]

✨ Context

Removes the src/gentropy/assets/data/variant_consequence_to_score.tsv file. This mapping between a variant conseauence and the impact score is now a config parameter of VariantIndexStep.
This feature was implemented in #805. Because I didn't know the file was a dependency of the VEP parser, this PR isolates the feature. The VEP parser now reads this property directly from the dataset.
I have run the variant index generation from all the VEP outputs produced in the last run and the mapping works properly.

variant_index.df.filter(f.size("transcriptConsequences") == 0).show()
+---------+----------+--------+---------------+---------------+------------------+-----------------------+------+----------------------+-----+-----------------+-------+
|variantId|chromosome|position|referenceAllele|alternateAllele|inSilicoPredictors|mostSevereConsequenceId|hgvsId|transcriptConsequences|rsIds|alleleFrequencies|dbXrefs|
+---------+----------+--------+---------------+---------------+------------------+-----------------------+------+----------------------+-----+-----------------+-------+
+---------+----------+--------+---------------+---------------+------------------+-----------------------+------+----------------------+-----+-----------------+-------+

🛠 What does this PR implement

• Deletes ``src/gentropy/assets/data/variant_consequence_to_score.tsv`
• Implements VariantIndexStep.consequence_to_pathogenicity_score
• Deletes VariantIndex.get_most_severe_gene_consequence, as this is already accessible in the VariantIndex dataset directly (transcriptConsequences.consequenceScore)

🙈 Missing

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[DSuveges]

Thank you for adjusting the code!