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.
Thinking about the future, there are more issues in cascading to preprocessed data. If we cascade to that, we will need then to cascade to processed data. Then we need to cascade to analyses, analyses chain and all jobs. Also, in order to do that we need to check that the processed data has not been used in any analysis that has been published...

We already had a discussion about cascading deletions and I don't think we can do that here. I suggest to do that in the next meeting and it should not block this PR.