Make the FASTA used in mappy a multi-FASTA format

[akikuno]

📋 Description

Currently, in DAJIN2, each allele's FASTA is split and mapped individually during mapping.

By consolidating these into a multi-FASTA format FASTA file, the cost of repeatedly invoking mappy can be minimized.

🔖 DAJIN2 Version

0.5.6

🔍 Environment

OS:
Python version:

📎 Anything else?

If there was a reason why it was necessary to split and map separately, that reason should be documented.