BLOCKER: Allow multiple templates per raw data

Multiple fixes in the PR:
- Allows multiple prep templates per raw data
- Preprocessed data is now linked with prep template rather than raw data
- Fixes #326 
- Changes on initialize.sql:
  - SPECTRA removed
  - SFF added
  - FASTA -> FASTA-Sanger

This PR allows @antgonza to continue with his PR.
I can see the pros/cons of both approaches. In an ideal world we shouldn't need to upload more than once or reprocesses any data cause all mapping files are perfect. However, this is not our reality. Thus, do not allow to erase only if EBI present.