[ADD] pipelines for the whole database

[jcapels]

Add pipelines for the whole database.

This will include an apache airflow ETL pipeline that will integrate and update the whole database of LIPID MAPS (https://www.lipidmaps.org/), SwissLipids (https://www.swisslipids.org/), and ModelSEED (https://modelseed.org/).

This will have to include

• the cross-references
• SMILES string
• hierarchy
• the relationship between alcohols and fatty acids with lipids
• biosynthetic relationships (that will have to be generated by hand-made reaction rules of RHEA reactions)

After that, a cronjob have to be run every month to integrate new data and update the database.