Add a feature to transpose many alignments

[hhandika]

This feature will allow users to transpose locus alignments to a sample-level sequence file and vice versa, depending on the input sequences. Currently, the feature is implemented in ULLAR. Because ULLAR already depended on SEGUL, it makes more sense to have the feature in SEGUL instead.

One possible scenario in which this feature is needed is for phasing UCE alleles. Current locus alignment:

locus1.fasta

>sequence_1
AGGGTC-
>sequence_2
AGGATCA

locus2.fasta

>sequence_1
TTGGTC-
>sequence_2
TTGATCA

After transposing them (note the resulting files are unaligned):

sequence_1.fasta

>locus1
AGGGTC
>locus2
TTGGTC

sequence_2.fasta

>locus1
AGGATCA
>locus2
TTGATCA