xMSannotator: Implement individual steps of the program as individual Galaxy tools

[hechth]

Since the workflow might have to be extended in the future, it would be good to split the whole workflow into the individual steps as standalone galaxy tools, similar to XCMS. This can already be done nicely with the clear structure in the refactored version.

Tools:

• Compute peak modules
• Simple annotation / database matching - should ideally be identical to only simple annotation as implemented currently
• Retention time clustering
• Mass defect computation
• Isotope detection
• Chemical score computation
• Pathway computation
• Computation of confidence levels
• Filtering of duplicates & boosting of expected compounds (suspect screening)