Create the first msp2model converter

[raar1]

• Add a msp2model directory to the base of aiproteomics (so that it would be accessible as aiproteomics.msp2model in the python package)
• Add a module containing a function that converts a provided, standard .msp spectral library file, into the raw input expected for the transformer retention time model (this is the model currently generated here, but that will be made into a model generator in issue Create the first model generator #19)
• Make converter flexible enough to handle e.g. different input sequence lengths
• Output as HDF5 containing the necessary input an output layer data for training

[raar1]

.msp reading should be done using the matchms library