MLST db-dl script no longer supported

[KasperThystrup]

Instead mlstdb should be downloaded by https://github.com/MDU-PHL/mlstdb

[RAHenriksen]

@KasperThystrup @SimoneScrima Then once one of you include this, then please move the actual mlst-db to the resources folder or (%database_path), so all database are found together.

1. This ensures the structure of all of our setup_dbs rules are following same structure
2. It also make the work of creating versions as output files such that it can be included in the different rules and long table format from Version numbers #33 much easier.

I assume this issue would then also be related to #86

[KasperThystrup]

Currently, I have removed the update rule entirely, as TSeeman have updated mlst for now, it requires reinstallation of the mlst env. But we might have to readress this issue in the future.