Add Raptor as a submodule

[MitraDarja]

Add Raptor as a submodule to make the same comparison as in the Raptor paper.
Note: The search probably needs to be adapted to the different methods.

[MitraDarja]

Reasons to add Raptor:

• The building process can be used without modification when providing a binary file with the precomputed submers
• Actual access to Raptors performance

Reasons to not add Raptor:

• Raptor is not a header library
• Search needs to be adapted/written anew
• There is no need for all its improvements like hibf, we are only interested in the accuracy

=> Instead of add Raptor as a submodule, we should use a simple ibf to determine FP and FN based on thresholds
(later we can also implement an adapted threshold)