D1 Migrate all data storage in bw2data to SQLite databases

[cmutel]

This is bring done in the file-remover-progressive branch (file-remover was a first try, but as it was everything at once it was impossible to get tests working for some sections, so is now abandoned), and is underway. Major tasks:

• mapping
• databases
• methods
• normalization and weighting
• config

[cmutel]

Need to create test cases using project backups (so that we keep the old structure) and migrations to the new format.

[cmutel]

Subtask D1.1: Migrate Method to use processed arrays directly