Update decision maker and stx DB

feat: update stx db (#25)

* hotfix: a bug was introduced due to comparing an uppercase stx type against a filename that went through .lower(), this fixes that

* WIP: update Dockerfile; add subunits to get_stx_db.py; improve messages; fix python version compatibility

* WIP: make the use of subunit B optional

* WIP: fix: reads missing alignment length

* fix: correct some positinal values, remove e-value from decision

* fix: ref_length assignment

* chore: update Dockerfile and reuse main script version

* feat: update stx db

* correct documentation

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Co-authored-by: Miguel Machado <miguelpaulo.machado@biomerieux.com>

GBS pili and surface protein typing

Added options to perform GBS pili and surface protein typing.
Downgraded Blast version of docker image due to headers incompatibility.
Added sequence length information in assembly mode.
Added possibility to write new alleles found.
Removed the culling limit during Blast search.
Added the possibility to change the number of reads mapping locations in reads mode.
Several bug fixes.

Assemblies

Allow typing from fasta files using Blast
Create specific module for E. coli stx subtyping
Create a script to update STX sequences from virulencefinder_db
Add Dengue virus serotyping/genotyping reference sequences
Update README
Minor fixes